[{"data":1,"prerenderedAt":19910},["ShallowReactive",2],{"note:cs\u002Fos\u002Freview\u002Fprob":3,"site-search-catalogue":19909},{"id":4,"title":5,"body":6,"description":9315,"extension":19903,"meta":19904,"navigation":12521,"path":19905,"seo":19906,"stem":19907,"__hash__":19908},"notes\u002Fsource\u002Fcs\u002Fos\u002Freview\u002Fprob.md","Prob",{"type":7,"value":8,"toc":19802},"minimark",[9,12,17,21,25,29,39,42,45,49,52,130,133,144,146,148,152,155,157,159,163,166,180,182,184,188,191,193,195,199,202,205,207,209,213,216,357,360,368,370,372,376,379,435,437,448,450,452,456,459,467,469,471,475,478,480,482,486,489,491,493,497,500,508,510,521,523,525,529,532,534,536,540,543,551,553,558,820,824,1190,1577,1649,2678,2688,2692,2695,2703,2705,2708,2711,2758,2960,3074,3077,3082,3290,3294,3449,3453,3456,3458,3461,3481,3485,3488,3493,3663,3744,3749,3752,3860,3865,4025,4103,4107,4110,4112,4115,4118,5159,5162,5167,5504,5509,6172,6176,6179,6181,6184,7157,7161,7164,7297,7299,7305,7307,7310,7324,7327,7332,7495,7500,7924,7933,7937,7940,7942,7945,8281,8285,8288,8390,8392,8400,8402,8405,8606,8609,8614,8861,8866,8985,9221,9226,9229,9233,9236,9238,9240,9244,9247,9255,9257,9259,9263,9266,9272,9274,9276,9280,9283,9288,9296,9298,9300,9304,9307,9316,9319,9325,9328,9330,9332,9336,9339,9341,9343,9347,9350,9352,9354,9358,9365,9367,9369,9373,9376,9378,9380,9384,9387,9395,9397,9399,9403,9406,9486,9489,9497,9499,9501,9505,9508,9519,9521,9525,9545,9548,9553,9573,9578,9596,9601,9618,9624,9628,9631,9633,9636,9639,9786,9791,9795,9798,9916,9918,9921,11302,11308,11519,11524,11528,11531,11627,11638,11640,11643,11648,11742,11747,11841,11854,11858,11861,11872,11874,11877,11882,11964,11969,12170,12175,12397,12402,12406,12409,12411,12414,12417,12455,12676,12688,12692,12695,12697,12700,12753,12758,12762,12765,12767,12770,12773,12799,12967,13032,13036,13039,13050,13052,13054,13058,13061,13063,13065,13069,13072,13080,13082,13084,13088,13091,13099,13101,13103,13107,13110,13152,13155,13163,13165,13167,13171,13174,13271,13274,13282,13284,13286,13290,13292,13294,13298,13301,13309,13311,13313,13317,13320,13337,13339,13341,13345,13348,13350,13353,13386,13389,13472,13477,14031,14035,14116,15145,15149,15229,15857,15861,15864,15868,15871,15954,15962,15964,15967,16231,16234,16238,17780,17784,17938,19705,19708,19798],[10,11],"hr",{},[13,14,16],"h2",{"id":15},"title-应用题order-7","title: 应用题\norder: 7",[18,19,20],"h1",{"id":20},"应用题",[13,22,24],{"id":23},"_1-磁道调度scan-与-sstf-算法","1. 磁道调度：SCAN 与 SSTF 算法",[26,27,28],"p",{},"假定当前磁头位于 100 号磁道，刚服务过 80 号磁道。进程对磁道的请求序列依次为 55，65，39，28，90，155，145，38，170。当采用扫描算法和最短寻道时间优先算法时，总的移动的磁道数分别是多少？（请给出寻道次序和每步移动磁道数）",[30,31,32,36],"ul",{},[33,34,35],"li",{},"(1) 采用扫描算法（寻道次序、每步移动磁道数和总的移动磁道数）。",[33,37,38],{},"(2) 最短寻道时间优先算法（寻道次序、每步移动磁道数和总的移动磁道数）。",[26,40,41],{},"::: details 解析",[26,43,44],{},":::",[13,46,48],{"id":47},"_2-银行家算法四类资源五进程","2. 银行家算法：四类资源、五进程",[26,50,51],{},"假设 UNIX 系统有 A、B、C、D 四类资源可供五个进程 P1、P2、P3、P4、P5 共享。系统对这四类资源的拥有量为: (3,14,12,12)。进程对资源的需求和分配情况如下：",[53,54,55,72],"table",{},[56,57,58],"thead",{},[59,60,61,66,69],"tr",{},[62,63,65],"th",{"align":64},"left","进程",[62,67,68],{"align":64},"已占有资源 (A, B, C, D)",[62,70,71],{"align":64},"最大需求数 (A, B, C, D)",[73,74,75,86,97,108,119],"tbody",{},[59,76,77,81,84],{},[78,79,80],"td",{"align":64},"P1",[78,82,83],{"align":64},"(0, 0, 1, 2)",[78,85,83],{"align":64},[59,87,88,91,94],{},[78,89,90],{"align":64},"P2",[78,92,93],{"align":64},"(1, 0, 0, 0)",[78,95,96],{"align":64},"(1, 7, 5, 0)",[59,98,99,102,105],{},[78,100,101],{"align":64},"P3",[78,103,104],{"align":64},"(1, 3, 5, 4)",[78,106,107],{"align":64},"(2, 3, 5, 6)",[59,109,110,113,116],{},[78,111,112],{"align":64},"P4",[78,114,115],{"align":64},"(0, 6, 3, 2)",[78,117,118],{"align":64},"(0, 6, 5, 2)",[59,120,121,124,127],{},[78,122,123],{"align":64},"P5",[78,125,126],{"align":64},"(0, 0, 1, 4)",[78,128,129],{"align":64},"(0, 6, 5, 6)",[26,131,132],{},"按银行家算法回答下列问题：",[30,134,135,138,141],{},[33,136,137],{},"(1) 系统是否处于安全状态？为什么？",[33,139,140],{},"(2) 如果 P2 提出请求 (0,4,2,0)，系统能否满足请求？请说明原因。",[33,142,143],{},"(3) 如果在 P2 提出资源需求 (0,4,2,0) 后，P3 提出资源需求 (0,0,0,1)，系统能否满足其请求？请说明原因。",[26,145,41],{},[26,147,44],{},[13,149,151],{"id":150},"_3-打印机共享设备的判断","3. 打印机：共享设备的判断",[26,153,154],{},"办公室只有一台打印机通过局域网为办公室人员提供打印服务。该打印机是共享设备的观点是否正确？为什么？",[26,156,41],{},[26,158,44],{},[13,160,162],{"id":161},"_4-请求分页逻辑地址转换与-lru","4. 请求分页：逻辑地址转换与 LRU",[26,164,165],{},"在请求分页系统中，有一个长度为 6 页的进程，页大小为 1KB。假如为它分配 3 个物理块，逻辑地址为：2049, 3098, 2078, 1066, 5018, 5163, 2088, 6010, 5069, 5287, 4000, 3068。试求出进程访问的页面次序，并用 LRU 页面置换算法计算出程序访问过程中所发生的缺页次数和缺页中断率。（说明：初始页面为空，计算为缺页。）",[30,167,168,171,174,177],{},[33,169,170],{},"(1) 进程访问的页面次序。",[33,172,173],{},"(2) LRU 页面置换算法计算出程序访问过程。",[33,175,176],{},"(3) 访问过程中所发生的缺页次数。",[33,178,179],{},"(4) 缺页中断率。",[26,181,41],{},[26,183,44],{},[13,185,187],{"id":186},"_5-页表项数正置页表与反置页表","5. 页表项数：正置页表与反置页表",[26,189,190],{},"一台机器有 48 位虚地址和 32 位物理地址，若页长为 8KB，问页表共有多少个页表项? 如果设计一个反置页表，则有多少个页表项?",[26,192,41],{},[26,194,44],{},[13,196,198],{"id":197},"_6-页面置换fifooptlru缺页次数","6. 页面置换（FIFO、OPT、LRU）缺页次数",[26,200,201],{},"在一个请求分页虚拟存储管理系统中，一个程序运行的页面走向是：\n1、2、3、4、2、1、5、6、2、1、2、3、7、6、3、2、1、2、3、6。",[26,203,204],{},"分别用 FIFO、OPT 和 LRU 算法，对分配给程序 3 个页框，求出缺页中断次数和缺页中断率。",[26,206,41],{},[26,208,44],{},[13,210,212],{"id":211},"_7-短作业优先抢占式调度时间表","7. 短作业优先（抢占式）调度时间表",[26,214,215],{},"若有一个四道作业系统，如果在一段时间内先后有 6 个作业，它们提交和运行时间由下表给出。作业采用短作业优先的调度算法，进程采用以剩余时间最短优先的抢占式调度算法。（说明：计算结果保留一位小数。）",[53,217,218,243],{},[56,219,220],{},[59,221,222,225,228,231,234,237,240],{},[62,223,224],{"align":64},"作业序号",[62,226,227],{"align":64},"提交时间",[62,229,230],{"align":64},"运行时间（分钟）",[62,232,233],{"align":64},"开始时间",[62,235,236],{"align":64},"结束时间",[62,238,239],{"align":64},"周转时间",[62,241,242],{"align":64},"带权周转时间",[73,244,245,264,283,302,320,339],{},[59,246,247,250,253,256,258,260,262],{},[78,248,249],{"align":64},"1",[78,251,252],{"align":64},"8:00",[78,254,255],{"align":64},"50",[78,257],{"align":64},[78,259],{"align":64},[78,261],{"align":64},[78,263],{"align":64},[59,265,266,269,272,275,277,279,281],{},[78,267,268],{"align":64},"2",[78,270,271],{"align":64},"8:15",[78,273,274],{"align":64},"30",[78,276],{"align":64},[78,278],{"align":64},[78,280],{"align":64},[78,282],{"align":64},[59,284,285,288,291,294,296,298,300],{},[78,286,287],{"align":64},"3",[78,289,290],{"align":64},"8:20",[78,292,293],{"align":64},"20",[78,295],{"align":64},[78,297],{"align":64},[78,299],{"align":64},[78,301],{"align":64},[59,303,304,307,310,312,314,316,318],{},[78,305,306],{"align":64},"4",[78,308,309],{"align":64},"8:25",[78,311,293],{"align":64},[78,313],{"align":64},[78,315],{"align":64},[78,317],{"align":64},[78,319],{"align":64},[59,321,322,325,328,331,333,335,337],{},[78,323,324],{"align":64},"5",[78,326,327],{"align":64},"8:30",[78,329,330],{"align":64},"10",[78,332],{"align":64},[78,334],{"align":64},[78,336],{"align":64},[78,338],{"align":64},[59,340,341,344,347,349,351,353,355],{},[78,342,343],{"align":64},"6",[78,345,346],{"align":64},"8:35",[78,348,324],{"align":64},[78,350],{"align":64},[78,352],{"align":64},[78,354],{"align":64},[78,356],{"align":64},[26,358,359],{},"问题：",[30,361,362,365],{},[33,363,364],{},"(1) 完成上表，给出各个作业的开始时间、完成时间、周转时间和带权周转时间；",[33,366,367],{},"(2) 计算平均作业周转时间和平均作业带权周转时间。",[26,369,41],{},[26,371,44],{},[13,373,375],{"id":374},"_8-银行家算法三类资源r1r2r3","8. 银行家算法：三类资源（R1\u002FR2\u002FR3）",[26,377,378],{},"设当前的系统状态如下表所示，系统此时 Available == (1,1,2)。",[53,380,381,393],{},[56,382,383],{},[59,384,385,387,390],{},[62,386,65],{"align":64},[62,388,389],{"align":64},"Claim (R1, R2, R3)",[62,391,392],{"align":64},"Allocation (R1, R2, R3)",[73,394,395,405,415,425],{},[59,396,397,399,402],{},[78,398,80],{"align":64},[78,400,401],{"align":64},"(3, 2, 2)",[78,403,404],{"align":64},"(1, 0, 0)",[59,406,407,409,412],{},[78,408,90],{"align":64},[78,410,411],{"align":64},"(6, 1, 3)",[78,413,414],{"align":64},"(5, 1, 1)",[59,416,417,419,422],{},[78,418,101],{"align":64},[78,420,421],{"align":64},"(3, 1, 4)",[78,423,424],{"align":64},"(2, 1, 1)",[59,426,427,429,432],{},[78,428,112],{"align":64},[78,430,431],{"align":64},"(4, 2, 2)",[78,433,434],{"align":64},"(0, 0, 2)",[26,436,359],{},[30,438,439,442,445],{},[33,440,441],{},"(1) 当 P2 发出资源请求向量 request2(1,0,1)，此时系统能否把资源分配给它？为什么？如果能分配给它，则请给出一个安全序列；",[33,443,444],{},"(2) 若在 P2 发出资源请求向量 request2(1,0,1) 后，若 P1 发出资源请求向量 request1(1,0,1)，此时系统能否把资源分配给它？为什么？",[33,446,447],{},"(3) 若在 P2 发出资源请求向量 request2(1,0,1) 后，若 P3 发出资源请求向量 request3(0,0,1)，此时系统能否把资源分配给它？为什么？",[26,449,41],{},[26,451,44],{},[13,453,455],{"id":454},"_9-磁道调度fcfsscansstf","9. 磁道调度（FCFS、SCAN、SSTF）",[26,457,458],{},"假定当前磁头位于 100 号磁道，刚服务过 105 号磁道。进程对磁道的请求序列依次为 55，34，58，39，18，90，160，45，145，38，170，180。当采用先来先服务算法、扫描算法和最短寻道时间优先算法时，总的移动的磁道数分别是多少？（请给出寻道次序、每步移动磁道数和总的移动磁道数）",[30,460,461,464],{},[33,462,463],{},"(1) 扫描算法",[33,465,466],{},"(2) 最短寻道时间优先算法",[26,468,41],{},[26,470,44],{},[13,472,474],{"id":473},"_10-二级页表虚地址结构","10. 二级页表虚地址结构",[26,476,477],{},"一个 32 位地址的计算机系统使用二级页表，虚地址被分为 9 位顶级页表，11 位二级页表和偏移。试问：页面长度是多少？虚地址空间共有多少个页面？",[26,479,41],{},[26,481,44],{},[13,483,485],{"id":484},"_11-虚地址转实地址十六进制","11. 虚地址转实地址（十六进制）",[26,487,488],{},"假设某虚存的用户空间为 1024KB，页面大小为 4KB，内存空间为 512KB。已知用户的虚页 10、11、12、13 页分得内存页框号为 62、78、25、36，求出虚地址 0BEBC（16 进制）的实地址（16 进制）是多少?",[26,490,41],{},[26,492,44],{},[13,494,496],{"id":495},"_12-两道程序并发运行时间图","12. 两道程序并发运行时间图",[26,498,499],{},"一个计算机系统，有一台输入机和一台打印机，现有两道程序设计投入运行，且程序 A 先开始做，程序 B 后开始运行。",[30,501,502,505],{},[33,503,504],{},"程序 A 的运行轨迹为：计算 50ms、打印 40ms、计算 80ms、打印 80ms，结束。",[33,506,507],{},"程序 B 的运行轨迹为：计算 50ms、输入 100ms、计算 40ms、打印 40ms，结束。",[26,509,359],{},[30,511,512,515,518],{},[33,513,514],{},"(1) 画出相应的运行图；",[33,516,517],{},"(2) 两道程序运行时，CPU 有无空闲等待？若有，在哪段时间等待？为什么？",[33,519,520],{},"(3) 程序 A、B 有无等待的情况？若有，指出发生等待的时刻。",[26,522,41],{},[26,524,44],{},[13,526,528],{"id":527},"_13-请求分页-lru页大小-100","13. 请求分页 LRU（页大小 100）",[26,530,531],{},"假设 UNIX 系统采用请求式分页存储，有一个长度为 6 页的进程，页大小为 100。假如为它分配 3 个物理块，逻辑地址为：021, 256, 301, 508, 279, 098, 334, 302, 578, 412。试求出进程访问的页面次序，并用 LRU 页面置换算法计算出程序访问过程，以及访问过程中所发生的缺页次数和缺页中断率。（说明：初始页面为空，计算为缺页。）",[26,533,41],{},[26,535,44],{},[13,537,539],{"id":538},"_14-磁盘交错存储6000rmin9扇区","14. 磁盘交错存储：6000r\u002Fmin、9扇区",[26,541,542],{},"假定磁盘转速为 6000r\u002Fmin（转\u002F分），磁盘格式化时每个盘面被分为 9 个扇区，现有一个文件共有 A，B，C，D，E，F，G，H，I 九个逻辑记录要存放在同一磁道上供处理程序使用，假设每个记录的大小与扇区的大小相同，处理程序每次从磁盘读出一个记录后要花 2.5ms 处理时间。若忽略其他辅助时间，请回答下列问题：",[30,544,545,548],{},[33,546,547],{},"（1）现在假设已经顺序存放好这 9 个记录，记录逆时针排列，磁盘顺时针旋转。那么读出该文件需要多少时间？",[33,549,550],{},"（2）为了使读出文件需要的时间最短，请重新调整各个记录的存放位置，画出各个记录的存放位置，计算该文件的读出时间。",[26,552,41],{},[554,555,557],"h3",{"id":556},"概念检查-concept-check","概念检查 (Concept Check)",[30,559,560,702,814],{},[33,561,562,566,567,701],{},[563,564,565],"strong",{},"磁盘周期计算："," 6000 r\u002Fmin = 100 转\u002F秒。因此，磁盘旋转一圈（1转）的时间 ",[568,569,572,624],"span",{"className":570},[571],"katex",[568,573,576],{"className":574},[575],"katex-mathml",[577,578,580],"math",{"xmlns":579},"http:\u002F\u002Fwww.w3.org\u002F1998\u002FMath\u002FMathML",[581,582,583,619],"semantics",{},[584,585,586,590,594,598,601,604,608,611,613,615,617],"mrow",{},[587,588,589],"mi",{},"T",[591,592,593],"mo",{},"=",[595,596,597],"mn",{},"1000",[587,599,600],{},"m",[587,602,603],{},"s",[587,605,607],{"mathvariant":606},"normal","\u002F",[595,609,610],{},"100",[591,612,593],{},[595,614,330],{},[587,616,600],{},[587,618,603],{},[620,621,623],"annotation",{"encoding":622},"application\u002Fx-tex","T = 1000ms \u002F 100 = 10ms",[568,625,629,656,685],{"className":626,"ariaHidden":628},[627],"katex-html","true",[568,630,633,638,644,649,653],{"className":631},[632],"base",[568,634],{"className":635,"style":637},[636],"strut","height:0.6833em;",[568,639,589],{"className":640,"style":643},[641,642],"mord","mathnormal","margin-right:0.1389em;",[568,645],{"className":646,"style":648},[647],"mspace","margin-right:0.2778em;",[568,650,593],{"className":651},[652],"mrel",[568,654],{"className":655,"style":648},[647],[568,657,659,663,666,669,672,676,679,682],{"className":658},[632],[568,660],{"className":661,"style":662},[636],"height:1em;vertical-align:-0.25em;",[568,664,597],{"className":665},[641],[568,667,600],{"className":668},[641,642],[568,670,603],{"className":671},[641,642],[568,673,675],{"className":674},[641],"\u002F100",[568,677],{"className":678,"style":648},[647],[568,680,593],{"className":681},[652],[568,683],{"className":684,"style":648},[647],[568,686,688,692,695,698],{"className":687},[632],[568,689],{"className":690,"style":691},[636],"height:0.6444em;",[568,693,330],{"className":694},[641],[568,696,600],{"className":697},[641,642],[568,699,603],{"className":700},[641,642],"。",[33,703,704,707,708,701],{},[563,705,706],{},"扇区读取时间："," 1圈有9个扇区，读取1个扇区（记录）的时间 ",[568,709,711,749],{"className":710},[571],[568,712,714],{"className":713},[575],[577,715,716],{"xmlns":579},[581,717,718,746],{},[584,719,720,723,725,727,729,731,733,736,739,742,744],{},[587,721,722],{},"t",[591,724,593],{},[595,726,330],{},[587,728,600],{},[587,730,603],{},[587,732,607],{"mathvariant":606},[595,734,735],{},"9",[591,737,738],{},"≈",[595,740,741],{},"1.11",[587,743,600],{},[587,745,603],{},[620,747,748],{"encoding":622},"t = 10ms \u002F 9 \\approx 1.11ms",[568,750,752,771,799],{"className":751,"ariaHidden":628},[627],[568,753,755,759,762,765,768],{"className":754},[632],[568,756],{"className":757,"style":758},[636],"height:0.6151em;",[568,760,722],{"className":761},[641,642],[568,763],{"className":764,"style":648},[647],[568,766,593],{"className":767},[652],[568,769],{"className":770,"style":648},[647],[568,772,774,777,780,783,786,790,793,796],{"className":773},[632],[568,775],{"className":776,"style":662},[636],[568,778,330],{"className":779},[641],[568,781,600],{"className":782},[641,642],[568,784,603],{"className":785},[641,642],[568,787,789],{"className":788},[641],"\u002F9",[568,791],{"className":792,"style":648},[647],[568,794,738],{"className":795},[652],[568,797],{"className":798,"style":648},[647],[568,800,802,805,808,811],{"className":801},[632],[568,803],{"className":804,"style":691},[636],[568,806,741],{"className":807},[641],[568,809,600],{"className":810},[641,642],[568,812,603],{"className":813},[641,642],[33,815,816,819],{},[563,817,818],{},"处理时间："," 给定为 2.5ms。",[554,821,823],{"id":822},"原理解析-the-why","原理解析 (The 'Why')",[26,825,826,829,830,962,963,1003,1004,1042,1043,1185,1186,1189],{},[563,827,828],{},"(1) 顺序存放时的困境：","\n当读完记录A（耗时 ",[568,831,833,856],{"className":832},[571],[568,834,836],{"className":835},[575],[577,837,838],{"xmlns":579},[581,839,840,853],{},[584,841,842,849,851],{},[843,844,845,847],"mfrac",{},[595,846,330],{},[595,848,735],{},[587,850,600],{},[587,852,603],{},[620,854,855],{"encoding":622},"\\frac{10}{9} ms",[568,857,859],{"className":858,"ariaHidden":628},[627],[568,860,862,866,956,959],{"className":861},[632],[568,863],{"className":864,"style":865},[636],"height:1.1901em;vertical-align:-0.345em;",[568,867,869,874,952],{"className":868},[641],[568,870],{"className":871},[872,873],"mopen","nulldelimiter",[568,875,877],{"className":876},[843],[568,878,882,943],{"className":879},[880,881],"vlist-t","vlist-t2",[568,883,886,938],{"className":884},[885],"vlist-r",[568,887,891,912,923],{"className":888,"style":890},[889],"vlist","height:0.8451em;",[568,892,894,899],{"style":893},"top:-2.655em;",[568,895],{"className":896,"style":898},[897],"pstrut","height:3em;",[568,900,906],{"className":901},[902,903,904,905],"sizing","reset-size6","size3","mtight",[568,907,909],{"className":908},[641,905],[568,910,735],{"className":911},[641,905],[568,913,915,918],{"style":914},"top:-3.23em;",[568,916],{"className":917,"style":898},[897],[568,919],{"className":920,"style":922},[921],"frac-line","border-bottom-width:0.04em;",[568,924,926,929],{"style":925},"top:-3.394em;",[568,927],{"className":928,"style":898},[897],[568,930,932],{"className":931},[902,903,904,905],[568,933,935],{"className":934},[641,905],[568,936,330],{"className":937},[641,905],[568,939,942],{"className":940},[941],"vlist-s","​",[568,944,946],{"className":945},[885],[568,947,950],{"className":948,"style":949},[889],"height:0.345em;",[568,951],{},[568,953],{"className":954},[955,873],"mclose",[568,957,600],{"className":958},[641,642],[568,960,603],{"className":961},[641,642],"）后，磁头来到了扇区1的末尾（即扇区2的开头）。此时处理程序开始处理A，耗时 ",[568,964,966,985],{"className":965},[571],[568,967,969],{"className":968},[575],[577,970,971],{"xmlns":579},[581,972,973,982],{},[584,974,975,978,980],{},[595,976,977],{},"2.5",[587,979,600],{},[587,981,603],{},[620,983,984],{"encoding":622},"2.5ms",[568,986,988],{"className":987,"ariaHidden":628},[627],[568,989,991,994,997,1000],{"className":990},[632],[568,992],{"className":993,"style":691},[636],[568,995,977],{"className":996},[641],[568,998,600],{"className":999},[641,642],[568,1001,603],{"className":1002},[641,642],"。\n在这 ",[568,1005,1007,1024],{"className":1006},[571],[568,1008,1010],{"className":1009},[575],[577,1011,1012],{"xmlns":579},[581,1013,1014,1022],{},[584,1015,1016,1018,1020],{},[595,1017,977],{},[587,1019,600],{},[587,1021,603],{},[620,1023,984],{"encoding":622},[568,1025,1027],{"className":1026,"ariaHidden":628},[627],[568,1028,1030,1033,1036,1039],{"className":1029},[632],[568,1031],{"className":1032,"style":691},[636],[568,1034,977],{"className":1035},[641],[568,1037,600],{"className":1038},[641,642],[568,1040,603],{"className":1041},[641,642]," 内，磁盘没有停下，它继续旋转了 ",[568,1044,1046,1080],{"className":1045},[571],[568,1047,1049],{"className":1048},[575],[577,1050,1051],{"xmlns":579},[581,1052,1053,1077],{},[584,1054,1055,1057,1059,1063,1069,1072,1074],{},[595,1056,977],{},[587,1058,607],{"mathvariant":606},[591,1060,1062],{"stretchy":1061},"false","(",[843,1064,1065,1067],{},[595,1066,330],{},[595,1068,735],{},[591,1070,1071],{"stretchy":1061},")",[591,1073,593],{},[595,1075,1076],{},"2.25",[620,1078,1079],{"encoding":622},"2.5 \u002F (\\frac{10}{9}) = 2.25",[568,1081,1083,1176],{"className":1082,"ariaHidden":628},[627],[568,1084,1086,1089,1093,1096,1164,1167,1170,1173],{"className":1085},[632],[568,1087],{"className":1088,"style":865},[636],[568,1090,1092],{"className":1091},[641],"2.5\u002F",[568,1094,1062],{"className":1095},[872],[568,1097,1099,1102,1161],{"className":1098},[641],[568,1100],{"className":1101},[872,873],[568,1103,1105],{"className":1104},[843],[568,1106,1108,1153],{"className":1107},[880,881],[568,1109,1111,1150],{"className":1110},[885],[568,1112,1114,1128,1136],{"className":1113,"style":890},[889],[568,1115,1116,1119],{"style":893},[568,1117],{"className":1118,"style":898},[897],[568,1120,1122],{"className":1121},[902,903,904,905],[568,1123,1125],{"className":1124},[641,905],[568,1126,735],{"className":1127},[641,905],[568,1129,1130,1133],{"style":914},[568,1131],{"className":1132,"style":898},[897],[568,1134],{"className":1135,"style":922},[921],[568,1137,1138,1141],{"style":925},[568,1139],{"className":1140,"style":898},[897],[568,1142,1144],{"className":1143},[902,903,904,905],[568,1145,1147],{"className":1146},[641,905],[568,1148,330],{"className":1149},[641,905],[568,1151,942],{"className":1152},[941],[568,1154,1156],{"className":1155},[885],[568,1157,1159],{"className":1158,"style":949},[889],[568,1160],{},[568,1162],{"className":1163},[955,873],[568,1165,1071],{"className":1166},[955],[568,1168],{"className":1169,"style":648},[647],[568,1171,593],{"className":1172},[652],[568,1174],{"className":1175,"style":648},[647],[568,1177,1179,1182],{"className":1178},[632],[568,1180],{"className":1181,"style":691},[636],[568,1183,1076],{"className":1184},[641]," 个扇区。\n也就是说，当A处理完时，磁头已经越过了记录B（紧挨着A），来到了扇区4的内部！为了读取B，磁头必须",[563,1187,1188],{},"傻傻地等待磁盘再转一整圈","，直到B再次转到磁头下方。",[30,1191,1192,1201,1303,1486],{},[33,1193,1194,1197,1198,701],{},[563,1195,1196],{},"读取并处理1个记录的总周期"," = 读出时间 + 处理时间 + 延迟等待下一个记录的时间 = ",[563,1199,1200],{},"刚好是磁盘旋转一圈的时间 (10ms)",[33,1202,1203,1204,701],{},"读前8个记录并找到下一个：",[568,1205,1207,1240],{"className":1206},[571],[568,1208,1210],{"className":1209},[575],[577,1211,1212],{"xmlns":579},[581,1213,1214,1237],{},[584,1215,1216,1219,1222,1224,1226,1228,1230,1233,1235],{},[595,1217,1218],{},"8",[591,1220,1221],{},"×",[595,1223,330],{},[587,1225,600],{},[587,1227,603],{},[591,1229,593],{},[595,1231,1232],{},"80",[587,1234,600],{},[587,1236,603],{},[620,1238,1239],{"encoding":622},"8 \\times 10ms = 80ms",[568,1241,1243,1264,1288],{"className":1242,"ariaHidden":628},[627],[568,1244,1246,1250,1253,1257,1261],{"className":1245},[632],[568,1247],{"className":1248,"style":1249},[636],"height:0.7278em;vertical-align:-0.0833em;",[568,1251,1218],{"className":1252},[641],[568,1254],{"className":1255,"style":1256},[647],"margin-right:0.2222em;",[568,1258,1221],{"className":1259},[1260],"mbin",[568,1262],{"className":1263,"style":1256},[647],[568,1265,1267,1270,1273,1276,1279,1282,1285],{"className":1266},[632],[568,1268],{"className":1269,"style":691},[636],[568,1271,330],{"className":1272},[641],[568,1274,600],{"className":1275},[641,642],[568,1277,603],{"className":1278},[641,642],[568,1280],{"className":1281,"style":648},[647],[568,1283,593],{"className":1284},[652],[568,1286],{"className":1287,"style":648},[647],[568,1289,1291,1294,1297,1300],{"className":1290},[632],[568,1292],{"className":1293,"style":691},[636],[568,1295,1232],{"className":1296},[641],[568,1298,600],{"className":1299},[641,642],[568,1301,603],{"className":1302},[641,642],[33,1304,1305,1306,1413,1414,701],{},"读出最后一个记录I读取 ",[568,1307,1309,1330],{"className":1308},[571],[568,1310,1312],{"className":1311},[575],[577,1313,1314],{"xmlns":579},[581,1315,1316,1328],{},[584,1317,1318,1324,1326],{},[843,1319,1320,1322],{},[595,1321,330],{},[595,1323,735],{},[587,1325,600],{},[587,1327,603],{},[620,1329,855],{"encoding":622},[568,1331,1333],{"className":1332,"ariaHidden":628},[627],[568,1334,1336,1339,1407,1410],{"className":1335},[632],[568,1337],{"className":1338,"style":865},[636],[568,1340,1342,1345,1404],{"className":1341},[641],[568,1343],{"className":1344},[872,873],[568,1346,1348],{"className":1347},[843],[568,1349,1351,1396],{"className":1350},[880,881],[568,1352,1354,1393],{"className":1353},[885],[568,1355,1357,1371,1379],{"className":1356,"style":890},[889],[568,1358,1359,1362],{"style":893},[568,1360],{"className":1361,"style":898},[897],[568,1363,1365],{"className":1364},[902,903,904,905],[568,1366,1368],{"className":1367},[641,905],[568,1369,735],{"className":1370},[641,905],[568,1372,1373,1376],{"style":914},[568,1374],{"className":1375,"style":898},[897],[568,1377],{"className":1378,"style":922},[921],[568,1380,1381,1384],{"style":925},[568,1382],{"className":1383,"style":898},[897],[568,1385,1387],{"className":1386},[902,903,904,905],[568,1388,1390],{"className":1389},[641,905],[568,1391,330],{"className":1392},[641,905],[568,1394,942],{"className":1395},[941],[568,1397,1399],{"className":1398},[885],[568,1400,1402],{"className":1401,"style":949},[889],[568,1403],{},[568,1405],{"className":1406},[955,873],[568,1408,600],{"className":1409},[641,642],[568,1411,603],{"className":1412},[641,642]," + 处理 ",[568,1415,1417,1444],{"className":1416},[571],[568,1418,1420],{"className":1419},[575],[577,1421,1422],{"xmlns":579},[581,1423,1424,1441],{},[584,1425,1426,1428,1430,1432,1434,1437,1439],{},[595,1427,977],{},[587,1429,600],{},[587,1431,603],{},[591,1433,593],{},[595,1435,1436],{},"3.61",[587,1438,600],{},[587,1440,603],{},[620,1442,1443],{"encoding":622},"2.5ms = 3.61ms",[568,1445,1447,1471],{"className":1446,"ariaHidden":628},[627],[568,1448,1450,1453,1456,1459,1462,1465,1468],{"className":1449},[632],[568,1451],{"className":1452,"style":691},[636],[568,1454,977],{"className":1455},[641],[568,1457,600],{"className":1458},[641,642],[568,1460,603],{"className":1461},[641,642],[568,1463],{"className":1464,"style":648},[647],[568,1466,593],{"className":1467},[652],[568,1469],{"className":1470,"style":648},[647],[568,1472,1474,1477,1480,1483],{"className":1473},[632],[568,1475],{"className":1476,"style":691},[636],[568,1478,1436],{"className":1479},[641],[568,1481,600],{"className":1482},[641,642],[568,1484,603],{"className":1485},[641,642],[33,1487,1488,1491,1492,701],{},[563,1489,1490],{},"总时间"," = ",[568,1493,1495,1523],{"className":1494},[571],[568,1496,1498],{"className":1497},[575],[577,1499,1500],{"xmlns":579},[581,1501,1502,1520],{},[584,1503,1504,1506,1509,1511,1513,1516,1518],{},[595,1505,1232],{},[591,1507,1508],{},"+",[595,1510,1436],{},[591,1512,593],{},[595,1514,1515],{},"83.61",[587,1517,600],{},[587,1519,603],{},[620,1521,1522],{"encoding":622},"80 + 3.61 = 83.61ms",[568,1524,1526,1544,1562],{"className":1525,"ariaHidden":628},[627],[568,1527,1529,1532,1535,1538,1541],{"className":1528},[632],[568,1530],{"className":1531,"style":1249},[636],[568,1533,1232],{"className":1534},[641],[568,1536],{"className":1537,"style":1256},[647],[568,1539,1508],{"className":1540},[1260],[568,1542],{"className":1543,"style":1256},[647],[568,1545,1547,1550,1553,1556,1559],{"className":1546},[632],[568,1548],{"className":1549,"style":691},[636],[568,1551,1436],{"className":1552},[641],[568,1554],{"className":1555,"style":648},[647],[568,1557,593],{"className":1558},[652],[568,1560],{"className":1561,"style":648},[647],[568,1563,1565,1568,1571,1574],{"className":1564},[632],[568,1566],{"className":1567,"style":691},[636],[568,1569,1515],{"className":1570},[641],[568,1572,600],{"className":1573},[641,642],[568,1575,603],{"className":1576},[641,642],[26,1578,1579,1582,1583,1611,1612,1615,1616,1644,1645,1648],{},[563,1580,1581],{},"(2) 最优化分布的设计：","\n既然处理A需要 ",[568,1584,1586,1599],{"className":1585},[571],[568,1587,1589],{"className":1588},[575],[577,1590,1591],{"xmlns":579},[581,1592,1593,1597],{},[584,1594,1595],{},[595,1596,1076],{},[620,1598,1076],{"encoding":622},[568,1600,1602],{"className":1601,"ariaHidden":628},[627],[568,1603,1605,1608],{"className":1604},[632],[568,1606],{"className":1607,"style":691},[636],[568,1609,1076],{"className":1610},[641]," 个扇区的时间，那我们何不",[563,1613,1614],{},"跳过这3个扇区","，直接把B放在磁头处理完A后刚刚好到达的地方呢？\n读完A，处理A用掉 ",[568,1617,1619,1632],{"className":1618},[571],[568,1620,1622],{"className":1621},[575],[577,1623,1624],{"xmlns":579},[581,1625,1626,1630],{},[584,1627,1628],{},[595,1629,1076],{},[620,1631,1076],{"encoding":622},[568,1633,1635],{"className":1634,"ariaHidden":628},[627],[568,1636,1638,1641],{"className":1637},[632],[568,1639],{"className":1640,"style":691},[636],[568,1642,1076],{"className":1643},[641]," 个扇区的时间，磁头滑过了 3 个扇区的起始位置。因此，逻辑上相邻的记录在物理位置上应该",[563,1646,1647],{},"间隔 3 个扇区","（即放在第4个位置）。",[30,1650,1651,1665],{},[33,1652,1653,1656,1657,1661],{},[563,1654,1655],{},"存放位置（按扇区0~8顺序列出）："," ",[1658,1659,1660],"code",{},"A, H, F, D, B, I, G, E, C",[1662,1663,1664],"em",{},"(推理：A在0，B在4，C在8，D在3，E在7，F在2，G在6，H在1，I在5)",[33,1666,1667,1670,1671,1903,1904,2126,2127,2349,2350,1491,2352,701],{},[563,1668,1669],{},"计算时间：","\n每个记录读取+处理+对齐耗时恰好为 4 个扇区的时间（",[568,1672,1674,1713],{"className":1673},[571],[568,1675,1677],{"className":1676},[575],[577,1678,1679],{"xmlns":579},[581,1680,1681,1710],{},[584,1682,1683,1685,1687,1693,1695,1697,1699,1706,1708],{},[595,1684,306],{},[591,1686,1221],{},[843,1688,1689,1691],{},[595,1690,330],{},[595,1692,735],{},[587,1694,600],{},[587,1696,603],{},[591,1698,593],{},[843,1700,1701,1704],{},[595,1702,1703],{},"40",[595,1705,735],{},[587,1707,600],{},[587,1709,603],{},[620,1711,1712],{"encoding":622},"4 \\times \\frac{10}{9}ms = \\frac{40}{9}ms",[568,1714,1716,1734,1823],{"className":1715,"ariaHidden":628},[627],[568,1717,1719,1722,1725,1728,1731],{"className":1718},[632],[568,1720],{"className":1721,"style":1249},[636],[568,1723,306],{"className":1724},[641],[568,1726],{"className":1727,"style":1256},[647],[568,1729,1221],{"className":1730},[1260],[568,1732],{"className":1733,"style":1256},[647],[568,1735,1737,1740,1808,1811,1814,1817,1820],{"className":1736},[632],[568,1738],{"className":1739,"style":865},[636],[568,1741,1743,1746,1805],{"className":1742},[641],[568,1744],{"className":1745},[872,873],[568,1747,1749],{"className":1748},[843],[568,1750,1752,1797],{"className":1751},[880,881],[568,1753,1755,1794],{"className":1754},[885],[568,1756,1758,1772,1780],{"className":1757,"style":890},[889],[568,1759,1760,1763],{"style":893},[568,1761],{"className":1762,"style":898},[897],[568,1764,1766],{"className":1765},[902,903,904,905],[568,1767,1769],{"className":1768},[641,905],[568,1770,735],{"className":1771},[641,905],[568,1773,1774,1777],{"style":914},[568,1775],{"className":1776,"style":898},[897],[568,1778],{"className":1779,"style":922},[921],[568,1781,1782,1785],{"style":925},[568,1783],{"className":1784,"style":898},[897],[568,1786,1788],{"className":1787},[902,903,904,905],[568,1789,1791],{"className":1790},[641,905],[568,1792,330],{"className":1793},[641,905],[568,1795,942],{"className":1796},[941],[568,1798,1800],{"className":1799},[885],[568,1801,1803],{"className":1802,"style":949},[889],[568,1804],{},[568,1806],{"className":1807},[955,873],[568,1809,600],{"className":1810},[641,642],[568,1812,603],{"className":1813},[641,642],[568,1815],{"className":1816,"style":648},[647],[568,1818,593],{"className":1819},[652],[568,1821],{"className":1822,"style":648},[647],[568,1824,1826,1829,1897,1900],{"className":1825},[632],[568,1827],{"className":1828,"style":865},[636],[568,1830,1832,1835,1894],{"className":1831},[641],[568,1833],{"className":1834},[872,873],[568,1836,1838],{"className":1837},[843],[568,1839,1841,1886],{"className":1840},[880,881],[568,1842,1844,1883],{"className":1843},[885],[568,1845,1847,1861,1869],{"className":1846,"style":890},[889],[568,1848,1849,1852],{"style":893},[568,1850],{"className":1851,"style":898},[897],[568,1853,1855],{"className":1854},[902,903,904,905],[568,1856,1858],{"className":1857},[641,905],[568,1859,735],{"className":1860},[641,905],[568,1862,1863,1866],{"style":914},[568,1864],{"className":1865,"style":898},[897],[568,1867],{"className":1868,"style":922},[921],[568,1870,1871,1874],{"style":925},[568,1872],{"className":1873,"style":898},[897],[568,1875,1877],{"className":1876},[902,903,904,905],[568,1878,1880],{"className":1879},[641,905],[568,1881,1703],{"className":1882},[641,905],[568,1884,942],{"className":1885},[941],[568,1887,1889],{"className":1888},[885],[568,1890,1892],{"className":1891,"style":949},[889],[568,1893],{},[568,1895],{"className":1896},[955,873],[568,1898,600],{"className":1899},[641,642],[568,1901,603],{"className":1902},[641,642],"）。\n前 8 个记录耗时：",[568,1905,1907,1942],{"className":1906},[571],[568,1908,1910],{"className":1909},[575],[577,1911,1912],{"xmlns":579},[581,1913,1914,1939],{},[584,1915,1916,1918,1920,1926,1928,1935,1937],{},[595,1917,1218],{},[591,1919,1221],{},[843,1921,1922,1924],{},[595,1923,1703],{},[595,1925,735],{},[591,1927,593],{},[843,1929,1930,1933],{},[595,1931,1932],{},"320",[595,1934,735],{},[587,1936,600],{},[587,1938,603],{},[620,1940,1941],{"encoding":622},"8 \\times \\frac{40}{9} = \\frac{320}{9} ms",[568,1943,1945,1963,2046],{"className":1944,"ariaHidden":628},[627],[568,1946,1948,1951,1954,1957,1960],{"className":1947},[632],[568,1949],{"className":1950,"style":1249},[636],[568,1952,1218],{"className":1953},[641],[568,1955],{"className":1956,"style":1256},[647],[568,1958,1221],{"className":1959},[1260],[568,1961],{"className":1962,"style":1256},[647],[568,1964,1966,1969,2037,2040,2043],{"className":1965},[632],[568,1967],{"className":1968,"style":865},[636],[568,1970,1972,1975,2034],{"className":1971},[641],[568,1973],{"className":1974},[872,873],[568,1976,1978],{"className":1977},[843],[568,1979,1981,2026],{"className":1980},[880,881],[568,1982,1984,2023],{"className":1983},[885],[568,1985,1987,2001,2009],{"className":1986,"style":890},[889],[568,1988,1989,1992],{"style":893},[568,1990],{"className":1991,"style":898},[897],[568,1993,1995],{"className":1994},[902,903,904,905],[568,1996,1998],{"className":1997},[641,905],[568,1999,735],{"className":2000},[641,905],[568,2002,2003,2006],{"style":914},[568,2004],{"className":2005,"style":898},[897],[568,2007],{"className":2008,"style":922},[921],[568,2010,2011,2014],{"style":925},[568,2012],{"className":2013,"style":898},[897],[568,2015,2017],{"className":2016},[902,903,904,905],[568,2018,2020],{"className":2019},[641,905],[568,2021,1703],{"className":2022},[641,905],[568,2024,942],{"className":2025},[941],[568,2027,2029],{"className":2028},[885],[568,2030,2032],{"className":2031,"style":949},[889],[568,2033],{},[568,2035],{"className":2036},[955,873],[568,2038],{"className":2039,"style":648},[647],[568,2041,593],{"className":2042},[652],[568,2044],{"className":2045,"style":648},[647],[568,2047,2049,2052,2120,2123],{"className":2048},[632],[568,2050],{"className":2051,"style":865},[636],[568,2053,2055,2058,2117],{"className":2054},[641],[568,2056],{"className":2057},[872,873],[568,2059,2061],{"className":2060},[843],[568,2062,2064,2109],{"className":2063},[880,881],[568,2065,2067,2106],{"className":2066},[885],[568,2068,2070,2084,2092],{"className":2069,"style":890},[889],[568,2071,2072,2075],{"style":893},[568,2073],{"className":2074,"style":898},[897],[568,2076,2078],{"className":2077},[902,903,904,905],[568,2079,2081],{"className":2080},[641,905],[568,2082,735],{"className":2083},[641,905],[568,2085,2086,2089],{"style":914},[568,2087],{"className":2088,"style":898},[897],[568,2090],{"className":2091,"style":922},[921],[568,2093,2094,2097],{"style":925},[568,2095],{"className":2096,"style":898},[897],[568,2098,2100],{"className":2099},[902,903,904,905],[568,2101,2103],{"className":2102},[641,905],[568,2104,1932],{"className":2105},[641,905],[568,2107,942],{"className":2108},[941],[568,2110,2112],{"className":2111},[885],[568,2113,2115],{"className":2114,"style":949},[889],[568,2116],{},[568,2118],{"className":2119},[955,873],[568,2121,600],{"className":2122},[641,642],[568,2124,603],{"className":2125},[641,642],"。\n第 9 个记录读出并处理：",[568,2128,2130,2165],{"className":2129},[571],[568,2131,2133],{"className":2132},[575],[577,2134,2135],{"xmlns":579},[581,2136,2137,2162],{},[584,2138,2139,2145,2147,2149,2151,2158,2160],{},[843,2140,2141,2143],{},[595,2142,330],{},[595,2144,735],{},[591,2146,1508],{},[595,2148,977],{},[591,2150,593],{},[843,2152,2153,2156],{},[595,2154,2155],{},"32.5",[595,2157,735],{},[587,2159,600],{},[587,2161,603],{},[620,2163,2164],{"encoding":622},"\\frac{10}{9} + 2.5 = \\frac{32.5}{9} ms",[568,2166,2168,2251,2269],{"className":2167,"ariaHidden":628},[627],[568,2169,2171,2174,2242,2245,2248],{"className":2170},[632],[568,2172],{"className":2173,"style":865},[636],[568,2175,2177,2180,2239],{"className":2176},[641],[568,2178],{"className":2179},[872,873],[568,2181,2183],{"className":2182},[843],[568,2184,2186,2231],{"className":2185},[880,881],[568,2187,2189,2228],{"className":2188},[885],[568,2190,2192,2206,2214],{"className":2191,"style":890},[889],[568,2193,2194,2197],{"style":893},[568,2195],{"className":2196,"style":898},[897],[568,2198,2200],{"className":2199},[902,903,904,905],[568,2201,2203],{"className":2202},[641,905],[568,2204,735],{"className":2205},[641,905],[568,2207,2208,2211],{"style":914},[568,2209],{"className":2210,"style":898},[897],[568,2212],{"className":2213,"style":922},[921],[568,2215,2216,2219],{"style":925},[568,2217],{"className":2218,"style":898},[897],[568,2220,2222],{"className":2221},[902,903,904,905],[568,2223,2225],{"className":2224},[641,905],[568,2226,330],{"className":2227},[641,905],[568,2229,942],{"className":2230},[941],[568,2232,2234],{"className":2233},[885],[568,2235,2237],{"className":2236,"style":949},[889],[568,2238],{},[568,2240],{"className":2241},[955,873],[568,2243],{"className":2244,"style":1256},[647],[568,2246,1508],{"className":2247},[1260],[568,2249],{"className":2250,"style":1256},[647],[568,2252,2254,2257,2260,2263,2266],{"className":2253},[632],[568,2255],{"className":2256,"style":691},[636],[568,2258,977],{"className":2259},[641],[568,2261],{"className":2262,"style":648},[647],[568,2264,593],{"className":2265},[652],[568,2267],{"className":2268,"style":648},[647],[568,2270,2272,2275,2343,2346],{"className":2271},[632],[568,2273],{"className":2274,"style":865},[636],[568,2276,2278,2281,2340],{"className":2277},[641],[568,2279],{"className":2280},[872,873],[568,2282,2284],{"className":2283},[843],[568,2285,2287,2332],{"className":2286},[880,881],[568,2288,2290,2329],{"className":2289},[885],[568,2291,2293,2307,2315],{"className":2292,"style":890},[889],[568,2294,2295,2298],{"style":893},[568,2296],{"className":2297,"style":898},[897],[568,2299,2301],{"className":2300},[902,903,904,905],[568,2302,2304],{"className":2303},[641,905],[568,2305,735],{"className":2306},[641,905],[568,2308,2309,2312],{"style":914},[568,2310],{"className":2311,"style":898},[897],[568,2313],{"className":2314,"style":922},[921],[568,2316,2317,2320],{"style":925},[568,2318],{"className":2319,"style":898},[897],[568,2321,2323],{"className":2322},[902,903,904,905],[568,2324,2326],{"className":2325},[641,905],[568,2327,2155],{"className":2328},[641,905],[568,2330,942],{"className":2331},[941],[568,2333,2335],{"className":2334},[885],[568,2336,2338],{"className":2337,"style":949},[889],[568,2339],{},[568,2341],{"className":2342},[955,873],[568,2344,600],{"className":2345},[641,642],[568,2347,603],{"className":2348},[641,642],"。\n",[563,2351,1490],{},[568,2353,2355,2406],{"className":2354},[571],[568,2356,2358],{"className":2357},[575],[577,2359,2360],{"xmlns":579},[581,2361,2362,2403],{},[584,2363,2364,2370,2372,2378,2380,2387,2389,2391,2393],{},[843,2365,2366,2368],{},[595,2367,1932],{},[595,2369,735],{},[591,2371,1508],{},[843,2373,2374,2376],{},[595,2375,2155],{},[595,2377,735],{},[591,2379,593],{},[843,2381,2382,2385],{},[595,2383,2384],{},"352.5",[595,2386,735],{},[587,2388,600],{},[587,2390,603],{},[591,2392,738],{},[584,2394,2395,2399,2401],{},[595,2396,2398],{"mathvariant":2397},"bold","39.17",[587,2400,600],{"mathvariant":2397},[587,2402,603],{"mathvariant":2397},[620,2404,2405],{"encoding":622},"\\frac{320}{9} + \\frac{32.5}{9} = \\frac{352.5}{9} ms \\approx \\mathbf{39.17 ms}",[568,2407,2409,2492,2575,2664],{"className":2408,"ariaHidden":628},[627],[568,2410,2412,2415,2483,2486,2489],{"className":2411},[632],[568,2413],{"className":2414,"style":865},[636],[568,2416,2418,2421,2480],{"className":2417},[641],[568,2419],{"className":2420},[872,873],[568,2422,2424],{"className":2423},[843],[568,2425,2427,2472],{"className":2426},[880,881],[568,2428,2430,2469],{"className":2429},[885],[568,2431,2433,2447,2455],{"className":2432,"style":890},[889],[568,2434,2435,2438],{"style":893},[568,2436],{"className":2437,"style":898},[897],[568,2439,2441],{"className":2440},[902,903,904,905],[568,2442,2444],{"className":2443},[641,905],[568,2445,735],{"className":2446},[641,905],[568,2448,2449,2452],{"style":914},[568,2450],{"className":2451,"style":898},[897],[568,2453],{"className":2454,"style":922},[921],[568,2456,2457,2460],{"style":925},[568,2458],{"className":2459,"style":898},[897],[568,2461,2463],{"className":2462},[902,903,904,905],[568,2464,2466],{"className":2465},[641,905],[568,2467,1932],{"className":2468},[641,905],[568,2470,942],{"className":2471},[941],[568,2473,2475],{"className":2474},[885],[568,2476,2478],{"className":2477,"style":949},[889],[568,2479],{},[568,2481],{"className":2482},[955,873],[568,2484],{"className":2485,"style":1256},[647],[568,2487,1508],{"className":2488},[1260],[568,2490],{"className":2491,"style":1256},[647],[568,2493,2495,2498,2566,2569,2572],{"className":2494},[632],[568,2496],{"className":2497,"style":865},[636],[568,2499,2501,2504,2563],{"className":2500},[641],[568,2502],{"className":2503},[872,873],[568,2505,2507],{"className":2506},[843],[568,2508,2510,2555],{"className":2509},[880,881],[568,2511,2513,2552],{"className":2512},[885],[568,2514,2516,2530,2538],{"className":2515,"style":890},[889],[568,2517,2518,2521],{"style":893},[568,2519],{"className":2520,"style":898},[897],[568,2522,2524],{"className":2523},[902,903,904,905],[568,2525,2527],{"className":2526},[641,905],[568,2528,735],{"className":2529},[641,905],[568,2531,2532,2535],{"style":914},[568,2533],{"className":2534,"style":898},[897],[568,2536],{"className":2537,"style":922},[921],[568,2539,2540,2543],{"style":925},[568,2541],{"className":2542,"style":898},[897],[568,2544,2546],{"className":2545},[902,903,904,905],[568,2547,2549],{"className":2548},[641,905],[568,2550,2155],{"className":2551},[641,905],[568,2553,942],{"className":2554},[941],[568,2556,2558],{"className":2557},[885],[568,2559,2561],{"className":2560,"style":949},[889],[568,2562],{},[568,2564],{"className":2565},[955,873],[568,2567],{"className":2568,"style":648},[647],[568,2570,593],{"className":2571},[652],[568,2573],{"className":2574,"style":648},[647],[568,2576,2578,2581,2649,2652,2655,2658,2661],{"className":2577},[632],[568,2579],{"className":2580,"style":865},[636],[568,2582,2584,2587,2646],{"className":2583},[641],[568,2585],{"className":2586},[872,873],[568,2588,2590],{"className":2589},[843],[568,2591,2593,2638],{"className":2592},[880,881],[568,2594,2596,2635],{"className":2595},[885],[568,2597,2599,2613,2621],{"className":2598,"style":890},[889],[568,2600,2601,2604],{"style":893},[568,2602],{"className":2603,"style":898},[897],[568,2605,2607],{"className":2606},[902,903,904,905],[568,2608,2610],{"className":2609},[641,905],[568,2611,735],{"className":2612},[641,905],[568,2614,2615,2618],{"style":914},[568,2616],{"className":2617,"style":898},[897],[568,2619],{"className":2620,"style":922},[921],[568,2622,2623,2626],{"style":925},[568,2624],{"className":2625,"style":898},[897],[568,2627,2629],{"className":2628},[902,903,904,905],[568,2630,2632],{"className":2631},[641,905],[568,2633,2384],{"className":2634},[641,905],[568,2636,942],{"className":2637},[941],[568,2639,2641],{"className":2640},[885],[568,2642,2644],{"className":2643,"style":949},[889],[568,2645],{},[568,2647],{"className":2648},[955,873],[568,2650,600],{"className":2651},[641,642],[568,2653,603],{"className":2654},[641,642],[568,2656],{"className":2657,"style":648},[647],[568,2659,738],{"className":2660},[652],[568,2662],{"className":2663,"style":648},[647],[568,2665,2667,2670],{"className":2666},[632],[568,2668],{"className":2669,"style":691},[636],[568,2671,2673],{"className":2672},[641],[568,2674,2677],{"className":2675},[641,2676],"mathbf","39.17ms",[26,2679,2680,2683,2684,2687],{},[563,2681,2682],{},"易错点："," 学生常常忘记磁盘在CPU处理数据时是",[563,2685,2686],{},"不会停下等你的","。必须把\"错过的扇区\"换算成下一圈的延迟时间。\n:::",[13,2689,2691],{"id":2690},"_15-磁盘交错存储20msr10扇区","15. 磁盘交错存储：20ms\u002Fr、10扇区",[26,2693,2694],{},"假定磁盘转速为 20ms\u002Fr，每个磁道被划分为 10 个扇区。现有 10 条记录存放在同一磁道上(一条记录正好与一个扇区的大小相等)，处理程序从磁盘读出一条记录需要 4ms，现要求按从 1 到 10 的顺序处理这 10 条记录。若磁头处于首条记录的起点位置，则：",[30,2696,2697,2700],{},[33,2698,2699],{},"(1) 按逆时针方向依次存放这 10 条记录(磁盘顺时针方向旋转)，处理程序读取这 10 条记录需要多长时间？",[33,2701,2702],{},"(2) 按最优化分布重新安排这 10 条记录，写出记录的逆时针存放顺序，并计算处理这 10 条记录需要的时间。",[26,2704,41],{},[554,2706,823],{"id":2707},"原理解析-the-why-1",[26,2709,2710],{},"这也是典型的**交错因子（Interleaving）**问题。",[30,2712,2713,2753],{},[33,2714,2715,2718,2719,1656,2750,701],{},[563,2716,2717],{},"转速与扇区："," 20ms\u002F圈，10个扇区\u002F圈 ",[568,2720,2722,2737],{"className":2721},[571],[568,2723,2725],{"className":2724},[575],[577,2726,2727],{"xmlns":579},[581,2728,2729,2734],{},[584,2730,2731],{},[591,2732,2733],{},"⇒",[620,2735,2736],{"encoding":622},"\\Rightarrow",[568,2738,2740],{"className":2739,"ariaHidden":628},[627],[568,2741,2743,2747],{"className":2742},[632],[568,2744],{"className":2745,"style":2746},[636],"height:0.3669em;",[568,2748,2733],{"className":2749},[652],[563,2751,2752],{},"读取 1 个扇区需要 2ms",[33,2754,2755,2757],{},[563,2756,818],{}," 给定为 4ms（注意，这4ms等于转过 2 个扇区的时间）。",[26,2759,2760,2763,2764,2794,2795,2834,2835,2919,2920,701],{},[563,2761,2762],{},"(1) 顺序存放：","\n读R1(2ms) ",[568,2765,2767,2782],{"className":2766},[571],[568,2768,2770],{"className":2769},[575],[577,2771,2772],{"xmlns":579},[581,2773,2774,2779],{},[584,2775,2776],{},[591,2777,2778],{},"→",[620,2780,2781],{"encoding":622},"\\rightarrow",[568,2783,2785],{"className":2784,"ariaHidden":628},[627],[568,2786,2788,2791],{"className":2787},[632],[568,2789],{"className":2790,"style":2746},[636],[568,2792,2778],{"className":2793},[652]," 处理R1(4ms)。此时磁盘转过了2个扇区，磁头来到了扇区3的起始位置。\n但我们需要读R2（在扇区1）。错过了！只能等磁盘再转一圈转回来。\n所以，处理一条记录的周期 = ",[568,2796,2798,2816],{"className":2797},[571],[568,2799,2801],{"className":2800},[575],[577,2802,2803],{"xmlns":579},[581,2804,2805,2813],{},[584,2806,2807,2809,2811],{},[595,2808,293],{},[587,2810,600],{},[587,2812,603],{},[620,2814,2815],{"encoding":622},"20ms",[568,2817,2819],{"className":2818,"ariaHidden":628},[627],[568,2820,2822,2825,2828,2831],{"className":2821},[632],[568,2823],{"className":2824,"style":691},[636],[568,2826,293],{"className":2827},[641],[568,2829,600],{"className":2830},[641,642],[568,2832,603],{"className":2833},[641,642]," (刚好一圈)。前9条需 ",[568,2836,2838,2865],{"className":2837},[571],[568,2839,2841],{"className":2840},[575],[577,2842,2843],{"xmlns":579},[581,2844,2845,2862],{},[584,2846,2847,2849,2851,2853,2855,2858,2860],{},[595,2848,735],{},[591,2850,1221],{},[595,2852,293],{},[591,2854,593],{},[595,2856,2857],{},"180",[587,2859,600],{},[587,2861,603],{},[620,2863,2864],{"encoding":622},"9 \\times 20 = 180ms",[568,2866,2868,2886,2904],{"className":2867,"ariaHidden":628},[627],[568,2869,2871,2874,2877,2880,2883],{"className":2870},[632],[568,2872],{"className":2873,"style":1249},[636],[568,2875,735],{"className":2876},[641],[568,2878],{"className":2879,"style":1256},[647],[568,2881,1221],{"className":2882},[1260],[568,2884],{"className":2885,"style":1256},[647],[568,2887,2889,2892,2895,2898,2901],{"className":2888},[632],[568,2890],{"className":2891,"style":691},[636],[568,2893,293],{"className":2894},[641],[568,2896],{"className":2897,"style":648},[647],[568,2899,593],{"className":2900},[652],[568,2902],{"className":2903,"style":648},[647],[568,2905,2907,2910,2913,2916],{"className":2906},[632],[568,2908],{"className":2909,"style":691},[636],[568,2911,2857],{"className":2912},[641],[568,2914,600],{"className":2915},[641,642],[568,2917,603],{"className":2918},[641,642],"。最后一条R10只需读取(2ms)和处理(4ms)，共6ms。总计 ",[568,2921,2923,2942],{"className":2922},[571],[568,2924,2926],{"className":2925},[575],[577,2927,2928],{"xmlns":579},[581,2929,2930,2939],{},[584,2931,2932,2935,2937],{},[595,2933,2934],{},"186",[587,2936,600],{},[587,2938,603],{},[620,2940,2941],{"encoding":622},"186ms",[568,2943,2945],{"className":2944,"ariaHidden":628},[627],[568,2946,2948,2951,2954,2957],{"className":2947},[632],[568,2949],{"className":2950,"style":691},[636],[568,2952,2934],{"className":2953},[641],[568,2955,600],{"className":2956},[641,642],[568,2958,603],{"className":2959},[641,642],[26,2961,2962,2965,2966,3069,3070,3073],{},[563,2963,2964],{},"(2) 最优化分布：","\n读完并处理完R1，一共耗时 ",[568,2967,2969,3003],{"className":2968},[571],[568,2970,2972],{"className":2971},[575],[577,2973,2974],{"xmlns":579},[581,2975,2976,3000],{},[584,2977,2978,2980,2982,2984,2986,2988,2990,2992,2994,2996,2998],{},[595,2979,268],{},[587,2981,600],{},[587,2983,603],{},[591,2985,1508],{},[595,2987,306],{},[587,2989,600],{},[587,2991,603],{},[591,2993,593],{},[595,2995,343],{},[587,2997,600],{},[587,2999,603],{},[620,3001,3002],{"encoding":622},"2ms + 4ms = 6ms",[568,3004,3006,3030,3054],{"className":3005,"ariaHidden":628},[627],[568,3007,3009,3012,3015,3018,3021,3024,3027],{"className":3008},[632],[568,3010],{"className":3011,"style":1249},[636],[568,3013,268],{"className":3014},[641],[568,3016,600],{"className":3017},[641,642],[568,3019,603],{"className":3020},[641,642],[568,3022],{"className":3023,"style":1256},[647],[568,3025,1508],{"className":3026},[1260],[568,3028],{"className":3029,"style":1256},[647],[568,3031,3033,3036,3039,3042,3045,3048,3051],{"className":3032},[632],[568,3034],{"className":3035,"style":691},[636],[568,3037,306],{"className":3038},[641],[568,3040,600],{"className":3041},[641,642],[568,3043,603],{"className":3044},[641,642],[568,3046],{"className":3047,"style":648},[647],[568,3049,593],{"className":3050},[652],[568,3052],{"className":3053,"style":648},[647],[568,3055,3057,3060,3063,3066],{"className":3056},[632],[568,3058],{"className":3059,"style":691},[636],[568,3061,343],{"className":3062},[641],[568,3064,600],{"className":3065},[641,642],[568,3067,603],{"className":3068},[641,642],"。此时磁头刚好完美对准了",[563,3071,3072],{},"第3个扇区","（偏移量为3，即扇区号3，如果起始为0）的起点！\n因此，不需要任何延迟，我们直接把 R2 放在扇区3即可。物理间隔为 3。",[554,3075,3076],{"id":3076},"答案与详细解答",[26,3078,3079],{},[563,3080,3081],{},"(1) 顺序存放的时间：",[30,3083,3084,3180,3285],{},[33,3085,3086,3087,701],{},"前9条记录，每条触发一次完整的20ms旋转周期：",[568,3088,3090,3120],{"className":3089},[571],[568,3091,3093],{"className":3092},[575],[577,3094,3095],{"xmlns":579},[581,3096,3097,3117],{},[584,3098,3099,3101,3103,3105,3107,3109,3111,3113,3115],{},[595,3100,735],{},[591,3102,1221],{},[595,3104,293],{},[587,3106,600],{},[587,3108,603],{},[591,3110,593],{},[595,3112,2857],{},[587,3114,600],{},[587,3116,603],{},[620,3118,3119],{"encoding":622},"9 \\times 20ms = 180ms",[568,3121,3123,3141,3165],{"className":3122,"ariaHidden":628},[627],[568,3124,3126,3129,3132,3135,3138],{"className":3125},[632],[568,3127],{"className":3128,"style":1249},[636],[568,3130,735],{"className":3131},[641],[568,3133],{"className":3134,"style":1256},[647],[568,3136,1221],{"className":3137},[1260],[568,3139],{"className":3140,"style":1256},[647],[568,3142,3144,3147,3150,3153,3156,3159,3162],{"className":3143},[632],[568,3145],{"className":3146,"style":691},[636],[568,3148,293],{"className":3149},[641],[568,3151,600],{"className":3152},[641,642],[568,3154,603],{"className":3155},[641,642],[568,3157],{"className":3158,"style":648},[647],[568,3160,593],{"className":3161},[652],[568,3163],{"className":3164,"style":648},[647],[568,3166,3168,3171,3174,3177],{"className":3167},[632],[568,3169],{"className":3170,"style":691},[636],[568,3172,2857],{"className":3173},[641],[568,3175,600],{"className":3176},[641,642],[568,3178,603],{"className":3179},[641,642],[33,3181,3182,3183,701],{},"第10条记录读取并处理：",[568,3184,3186,3219],{"className":3185},[571],[568,3187,3189],{"className":3188},[575],[577,3190,3191],{"xmlns":579},[581,3192,3193,3217],{},[584,3194,3195,3197,3199,3201,3203,3205,3207,3209,3211,3213,3215],{},[595,3196,268],{},[587,3198,600],{},[587,3200,603],{},[591,3202,1508],{},[595,3204,306],{},[587,3206,600],{},[587,3208,603],{},[591,3210,593],{},[595,3212,343],{},[587,3214,600],{},[587,3216,603],{},[620,3218,3002],{"encoding":622},[568,3220,3222,3246,3270],{"className":3221,"ariaHidden":628},[627],[568,3223,3225,3228,3231,3234,3237,3240,3243],{"className":3224},[632],[568,3226],{"className":3227,"style":1249},[636],[568,3229,268],{"className":3230},[641],[568,3232,600],{"className":3233},[641,642],[568,3235,603],{"className":3236},[641,642],[568,3238],{"className":3239,"style":1256},[647],[568,3241,1508],{"className":3242},[1260],[568,3244],{"className":3245,"style":1256},[647],[568,3247,3249,3252,3255,3258,3261,3264,3267],{"className":3248},[632],[568,3250],{"className":3251,"style":691},[636],[568,3253,306],{"className":3254},[641],[568,3256,600],{"className":3257},[641,642],[568,3259,603],{"className":3260},[641,642],[568,3262],{"className":3263,"style":648},[647],[568,3265,593],{"className":3266},[652],[568,3268],{"className":3269,"style":648},[647],[568,3271,3273,3276,3279,3282],{"className":3272},[632],[568,3274],{"className":3275,"style":691},[636],[568,3277,343],{"className":3278},[641],[568,3280,600],{"className":3281},[641,642],[568,3283,603],{"className":3284},[641,642],[33,3286,3287,701],{},[563,3288,3289],{},"总时间 = 186 ms",[26,3291,3292],{},[563,3293,2964],{},[30,3295,3296,3307],{},[33,3297,3298,1656,3301,2349,3304],{},[563,3299,3300],{},"存放顺序（按物理扇区 0~9 列出）：",[1658,3302,3303],{},"1, 8, 5, 2, 9, 6, 3, 10, 7, 4",[1662,3305,3306],{},"(推理：R1在0，R2在3，R3在6，R4在9，R5在2，R6在5，R7在8，R8在1，R9在4，R10在7)",[33,3308,3309,3311,3312,3448],{},[563,3310,818],{},"\n因为布局完美无缝衔接，没有任何旋转延迟。\n10条记录的 (读取 + 处理) = ",[568,3313,3315,3360],{"className":3314},[571],[568,3316,3318],{"className":3317},[575],[577,3319,3320],{"xmlns":579},[581,3321,3322,3357],{},[584,3323,3324,3326,3328,3330,3332,3334,3336,3338,3340,3342,3344,3346,3348],{},[595,3325,330],{},[591,3327,1221],{},[591,3329,1062],{"stretchy":1061},[595,3331,268],{},[587,3333,600],{},[587,3335,603],{},[591,3337,1508],{},[595,3339,306],{},[587,3341,600],{},[587,3343,603],{},[591,3345,1071],{"stretchy":1061},[591,3347,593],{},[584,3349,3350,3353,3355],{},[595,3351,3352],{"mathvariant":2397},"60",[587,3354,600],{"mathvariant":2397},[587,3356,603],{"mathvariant":2397},[620,3358,3359],{"encoding":622},"10 \\times (2ms + 4ms) = \\mathbf{60 ms}",[568,3361,3363,3381,3408,3435],{"className":3362,"ariaHidden":628},[627],[568,3364,3366,3369,3372,3375,3378],{"className":3365},[632],[568,3367],{"className":3368,"style":1249},[636],[568,3370,330],{"className":3371},[641],[568,3373],{"className":3374,"style":1256},[647],[568,3376,1221],{"className":3377},[1260],[568,3379],{"className":3380,"style":1256},[647],[568,3382,3384,3387,3390,3393,3396,3399,3402,3405],{"className":3383},[632],[568,3385],{"className":3386,"style":662},[636],[568,3388,1062],{"className":3389},[872],[568,3391,268],{"className":3392},[641],[568,3394,600],{"className":3395},[641,642],[568,3397,603],{"className":3398},[641,642],[568,3400],{"className":3401,"style":1256},[647],[568,3403,1508],{"className":3404},[1260],[568,3406],{"className":3407,"style":1256},[647],[568,3409,3411,3414,3417,3420,3423,3426,3429,3432],{"className":3410},[632],[568,3412],{"className":3413,"style":662},[636],[568,3415,306],{"className":3416},[641],[568,3418,600],{"className":3419},[641,642],[568,3421,603],{"className":3422},[641,642],[568,3424,1071],{"className":3425},[955],[568,3427],{"className":3428,"style":648},[647],[568,3430,593],{"className":3431},[652],[568,3433],{"className":3434,"style":648},[647],[568,3436,3438,3441],{"className":3437},[632],[568,3439],{"className":3440,"style":691},[636],[568,3442,3444],{"className":3443},[641],[568,3445,3447],{"className":3446},[641,2676],"60ms","。\n:::",[13,3450,3452],{"id":3451},"_16-页面置换fifooptlru缺页中断率","16. 页面置换（FIFO\u002FOPT\u002FLRU）缺页中断率",[26,3454,3455],{},"一个页式存储管理系统使用 FIFO、OPT 和 LRU 页面替换算法，如果作业的页面走向为：2、3、2、1、5、2、4、5、3、2、5、2。分配给作业的物理块数分别为 3。假设初始页面为空，给出页面置换过程，并计算访问过程中发生的缺页中断次数和缺页中断率。",[26,3457,41],{},[554,3459,557],{"id":3460},"概念检查-concept-check-1",[30,3462,3463,3469,3475],{},[33,3464,3465,3468],{},[563,3466,3467],{},"FIFO (先进先出):"," 淘汰驻留内存时间最长的页。",[33,3470,3471,3474],{},[563,3472,3473],{},"OPT (最佳置换):"," 淘汰未来最长时间内不再被访问的页（神仙算法，往后看）。",[33,3476,3477,3480],{},[563,3478,3479],{},"LRU (最近最久未使用):"," 淘汰历史中最长时间没有被访问过的页（往前看）。",[554,3482,3484],{"id":3483},"答案与详细解答-过程模拟表","答案与详细解答 (过程模拟表)",[26,3486,3487],{},"序列： 2, 3, 2, 1, 5, 2, 4, 5, 3, 2, 5, 2 （总长 12）",[26,3489,3490],{},[563,3491,3492],{},"(1) FIFO 算法",[53,3494,3495,3526],{},[56,3496,3497],{},[59,3498,3499,3502,3504,3506,3508,3510,3512,3514,3516,3518,3520,3522,3524],{},[62,3500,3501],{"align":64},"页面走向",[62,3503,268],{"align":64},[62,3505,287],{"align":64},[62,3507,268],{"align":64},[62,3509,249],{"align":64},[62,3511,324],{"align":64},[62,3513,268],{"align":64},[62,3515,306],{"align":64},[62,3517,324],{"align":64},[62,3519,287],{"align":64},[62,3521,268],{"align":64},[62,3523,324],{"align":64},[62,3525,268],{"align":64},[73,3527,3528,3563,3598,3633],{},[59,3529,3530,3533,3537,3539,3541,3543,3547,3549,3551,3553,3557,3559,3561],{},[78,3531,3532],{"align":64},"物理块1",[78,3534,3535],{"align":64},[563,3536,268],{},[78,3538,268],{"align":64},[78,3540,268],{"align":64},[78,3542,268],{"align":64},[78,3544,3545],{"align":64},[563,3546,324],{},[78,3548,324],{"align":64},[78,3550,324],{"align":64},[78,3552,324],{"align":64},[78,3554,3555],{"align":64},[563,3556,287],{},[78,3558,287],{"align":64},[78,3560,287],{"align":64},[78,3562,287],{"align":64},[59,3564,3565,3568,3570,3574,3576,3578,3580,3584,3586,3588,3590,3594,3596],{},[78,3566,3567],{"align":64},"物理块2",[78,3569],{"align":64},[78,3571,3572],{"align":64},[563,3573,287],{},[78,3575,287],{"align":64},[78,3577,287],{"align":64},[78,3579,287],{"align":64},[78,3581,3582],{"align":64},[563,3583,268],{},[78,3585,268],{"align":64},[78,3587,268],{"align":64},[78,3589,268],{"align":64},[78,3591,3592],{"align":64},[563,3593,324],{},[78,3595,324],{"align":64},[78,3597,324],{"align":64},[59,3599,3600,3603,3605,3607,3609,3613,3615,3617,3621,3623,3625,3627,3631],{},[78,3601,3602],{"align":64},"物理块3",[78,3604],{"align":64},[78,3606],{"align":64},[78,3608],{"align":64},[78,3610,3611],{"align":64},[563,3612,249],{},[78,3614,249],{"align":64},[78,3616,249],{"align":64},[78,3618,3619],{"align":64},[563,3620,306],{},[78,3622,306],{"align":64},[78,3624,306],{"align":64},[78,3626,306],{"align":64},[78,3628,3629],{"align":64},[563,3630,268],{},[78,3632,268],{"align":64},[59,3634,3635,3638,3641,3643,3645,3647,3649,3651,3653,3655,3657,3659,3661],{},[78,3636,3637],{"align":64},"是否缺页",[78,3639,3640],{"align":64},"F",[78,3642,3640],{"align":64},[78,3644],{"align":64},[78,3646,3640],{"align":64},[78,3648,3640],{"align":64},[78,3650,3640],{"align":64},[78,3652,3640],{"align":64},[78,3654],{"align":64},[78,3656,3640],{"align":64},[78,3658,3640],{"align":64},[78,3660],{"align":64},[78,3662,3640],{"align":64},[30,3664,3665,3671],{},[33,3666,3667,3670],{},[563,3668,3669],{},"缺页次数："," 9次",[33,3672,3673,1656,3676],{},[563,3674,3675],{},"缺页中断率：",[568,3677,3679,3708],{"className":3678},[571],[568,3680,3682],{"className":3681},[575],[577,3683,3684],{"xmlns":579},[581,3685,3686,3705],{},[584,3687,3688,3690,3692,3695,3697],{},[595,3689,735],{},[587,3691,607],{"mathvariant":606},[595,3693,3694],{},"12",[591,3696,593],{},[584,3698,3699,3702],{},[595,3700,3701],{"mathvariant":2397},"75",[587,3703,3704],{"mathvariant":2397},"%",[620,3706,3707],{"encoding":622},"9 \u002F 12 = \\mathbf{75\\%}",[568,3709,3711,3730],{"className":3710,"ariaHidden":628},[627],[568,3712,3714,3717,3721,3724,3727],{"className":3713},[632],[568,3715],{"className":3716,"style":662},[636],[568,3718,3720],{"className":3719},[641],"9\u002F12",[568,3722],{"className":3723,"style":648},[647],[568,3725,593],{"className":3726},[652],[568,3728],{"className":3729,"style":648},[647],[568,3731,3733,3737],{"className":3732},[632],[568,3734],{"className":3735,"style":3736},[636],"height:0.8056em;vertical-align:-0.0556em;",[568,3738,3740],{"className":3739},[641],[568,3741,3743],{"className":3742},[641,2676],"75%",[26,3745,3746],{},[563,3747,3748],{},"(2) OPT 算法 (向右看，淘汰最晚出现的)",[26,3750,3751],{},"修正后的OPT过程：",[30,3753,3754,3757,3764,3767,3774,3777,3784,3787,3792],{},[33,3755,3756],{},"进1: 内存有2,3,1。",[33,3758,3759,3760,3763],{},"进5: 往后看未来是 ",[1658,3761,3762],{},"2,4,5,3...","，1再也不出现，淘汰1。块变为2,3,5。",[33,3765,3766],{},"进2: 命中。",[33,3768,3769,3770,3773],{},"进4: 往后看 ",[1658,3771,3772],{},"5,3,2,5,2","，3和2和5都会用，3最晚出现，淘汰3。块变为2,5,4。",[33,3775,3776],{},"进5: 命中。",[33,3778,3779,3780,3783],{},"进3: 往后看 ",[1658,3781,3782],{},"2,5,2","，4再也不用，淘汰4。块变为2,5,3。",[33,3785,3786],{},"后续全部命中。",[33,3788,3789,3791],{},[563,3790,3669],{}," 6次",[33,3793,3794,1656,3796],{},[563,3795,3675],{},[568,3797,3799,3825],{"className":3798},[571],[568,3800,3802],{"className":3801},[575],[577,3803,3804],{"xmlns":579},[581,3805,3806,3822],{},[584,3807,3808,3810,3812,3814,3816],{},[595,3809,343],{},[587,3811,607],{"mathvariant":606},[595,3813,3694],{},[591,3815,593],{},[584,3817,3818,3820],{},[595,3819,255],{"mathvariant":2397},[587,3821,3704],{"mathvariant":2397},[620,3823,3824],{"encoding":622},"6 \u002F 12 = \\mathbf{50\\%}",[568,3826,3828,3847],{"className":3827,"ariaHidden":628},[627],[568,3829,3831,3834,3838,3841,3844],{"className":3830},[632],[568,3832],{"className":3833,"style":662},[636],[568,3835,3837],{"className":3836},[641],"6\u002F12",[568,3839],{"className":3840,"style":648},[647],[568,3842,593],{"className":3843},[652],[568,3845],{"className":3846,"style":648},[647],[568,3848,3850,3853],{"className":3849},[632],[568,3851],{"className":3852,"style":3736},[636],[568,3854,3856],{"className":3855},[641],[568,3857,3859],{"className":3858},[641,2676],"50%",[26,3861,3862],{},[563,3863,3864],{},"(3) LRU 算法 (向左看，淘汰最久未用的)",[53,3866,3867,3897],{},[56,3868,3869],{},[59,3870,3871,3873,3875,3877,3879,3881,3883,3885,3887,3889,3891,3893,3895],{},[62,3872,3501],{"align":64},[62,3874,268],{"align":64},[62,3876,287],{"align":64},[62,3878,268],{"align":64},[62,3880,249],{"align":64},[62,3882,324],{"align":64},[62,3884,268],{"align":64},[62,3886,306],{"align":64},[62,3888,324],{"align":64},[62,3890,287],{"align":64},[62,3892,268],{"align":64},[62,3894,324],{"align":64},[62,3896,268],{"align":64},[73,3898,3899,3931,3963,3997],{},[59,3900,3901,3903,3907,3909,3911,3913,3915,3917,3919,3921,3925,3927,3929],{},[78,3902,3532],{"align":64},[78,3904,3905],{"align":64},[563,3906,268],{},[78,3908,268],{"align":64},[78,3910,268],{"align":64},[78,3912,268],{"align":64},[78,3914,268],{"align":64},[78,3916,268],{"align":64},[78,3918,268],{"align":64},[78,3920,268],{"align":64},[78,3922,3923],{"align":64},[563,3924,287],{},[78,3926,287],{"align":64},[78,3928,287],{"align":64},[78,3930,287],{"align":64},[59,3932,3933,3935,3937,3941,3943,3945,3949,3951,3953,3955,3957,3959,3961],{},[78,3934,3567],{"align":64},[78,3936],{"align":64},[78,3938,3939],{"align":64},[563,3940,287],{},[78,3942,287],{"align":64},[78,3944,287],{"align":64},[78,3946,3947],{"align":64},[563,3948,324],{},[78,3950,324],{"align":64},[78,3952,324],{"align":64},[78,3954,324],{"align":64},[78,3956,324],{"align":64},[78,3958,324],{"align":64},[78,3960,324],{"align":64},[78,3962,324],{"align":64},[59,3964,3965,3967,3969,3971,3973,3977,3979,3981,3985,3987,3989,3993,3995],{},[78,3966,3602],{"align":64},[78,3968],{"align":64},[78,3970],{"align":64},[78,3972],{"align":64},[78,3974,3975],{"align":64},[563,3976,249],{},[78,3978,249],{"align":64},[78,3980,249],{"align":64},[78,3982,3983],{"align":64},[563,3984,306],{},[78,3986,306],{"align":64},[78,3988,306],{"align":64},[78,3990,3991],{"align":64},[563,3992,268],{},[78,3994,268],{"align":64},[78,3996,268],{"align":64},[59,3998,3999,4001,4003,4005,4007,4009,4011,4013,4015,4017,4019,4021,4023],{},[78,4000,3637],{"align":64},[78,4002,3640],{"align":64},[78,4004,3640],{"align":64},[78,4006],{"align":64},[78,4008,3640],{"align":64},[78,4010,3640],{"align":64},[78,4012],{"align":64},[78,4014,3640],{"align":64},[78,4016],{"align":64},[78,4018,3640],{"align":64},[78,4020,3640],{"align":64},[78,4022],{"align":64},[78,4024],{"align":64},[30,4026,4027,4032],{},[33,4028,4029,4031],{},[563,4030,3669],{}," 7次",[33,4033,4034,1656,4036,4102],{},[563,4035,3675],{},[568,4037,4039,4067],{"className":4038},[571],[568,4040,4042],{"className":4041},[575],[577,4043,4044],{"xmlns":579},[581,4045,4046,4064],{},[584,4047,4048,4051,4053,4055,4057],{},[595,4049,4050],{},"7",[587,4052,607],{"mathvariant":606},[595,4054,3694],{},[591,4056,738],{},[584,4058,4059,4062],{},[595,4060,4061],{"mathvariant":2397},"58.3",[587,4063,3704],{"mathvariant":2397},[620,4065,4066],{"encoding":622},"7 \u002F 12 \\approx \\mathbf{58.3\\%}",[568,4068,4070,4089],{"className":4069,"ariaHidden":628},[627],[568,4071,4073,4076,4080,4083,4086],{"className":4072},[632],[568,4074],{"className":4075,"style":662},[636],[568,4077,4079],{"className":4078},[641],"7\u002F12",[568,4081],{"className":4082,"style":648},[647],[568,4084,738],{"className":4085},[652],[568,4087],{"className":4088,"style":648},[647],[568,4090,4092,4095],{"className":4091},[632],[568,4093],{"className":4094,"style":3736},[636],[568,4096,4098],{"className":4097},[641],[568,4099,4101],{"className":4100},[641,2676],"58.3%","\n:::",[13,4104,4106],{"id":4105},"_17-多级存储器有效访问时间eat","17. 多级存储器有效访问时间（EAT）",[26,4108,4109],{},"某计算机有缓存、内存、辅存来实现虚拟存储器。如果数据在缓存中，访问它需要 Ans；如果在内存但不在缓存，需要 Bns 将其装入缓存，然后才能访问；如果不在内存而在辅存，需要 Cns 将其读入内存，然后，用 Bns 再读入缓存，然后才能访问。假设缓存命中率为 (n-1)\u002Fn，内存命中率为 (m-1)\u002Fm。给出数据在缓存、内存、以及辅存中比率，并计算数据平均访问时间。",[26,4111,41],{},[554,4113,823],{"id":4114},"原理解析-the-why-2",[26,4116,4117],{},"这是经典的多级存储器有效访问时间（EAT）计算。",[30,4119,4120,4367,4707],{},[33,4121,4122,1656,4125,4337,4338,701],{},[563,4123,4124],{},"命中缓存的概率：",[568,4126,4128,4178],{"className":4127},[571],[568,4129,4131],{"className":4130},[575],[577,4132,4133],{"xmlns":579},[581,4134,4135,4175],{},[584,4136,4137,4159,4161],{},[4138,4139,4140,4143],"msub",{},[587,4141,4142],{},"P",[584,4144,4145,4148,4151,4153,4156],{},[587,4146,4147],{},"c",[587,4149,4150],{},"a",[587,4152,4147],{},[587,4154,4155],{},"h",[587,4157,4158],{},"e",[591,4160,593],{},[843,4162,4163,4173],{},[584,4164,4165,4168,4171],{},[587,4166,4167],{},"n",[591,4169,4170],{},"−",[595,4172,249],{},[587,4174,4167],{},[620,4176,4177],{"encoding":622},"P_{cache} = \\frac{n-1}{n}",[568,4179,4181,4257],{"className":4180,"ariaHidden":628},[627],[568,4182,4184,4188,4248,4251,4254],{"className":4183},[632],[568,4185],{"className":4186,"style":4187},[636],"height:0.8333em;vertical-align:-0.15em;",[568,4189,4191,4194],{"className":4190},[641],[568,4192,4142],{"className":4193,"style":643},[641,642],[568,4195,4198],{"className":4196},[4197],"msupsub",[568,4199,4201,4239],{"className":4200},[880,881],[568,4202,4204,4236],{"className":4203},[885],[568,4205,4208],{"className":4206,"style":4207},[889],"height:0.3361em;",[568,4209,4211,4215],{"style":4210},"top:-2.55em;margin-left:-0.1389em;margin-right:0.05em;",[568,4212],{"className":4213,"style":4214},[897],"height:2.7em;",[568,4216,4218],{"className":4217},[902,903,904,905],[568,4219,4221,4224,4227,4230,4233],{"className":4220},[641,905],[568,4222,4147],{"className":4223},[641,642,905],[568,4225,4150],{"className":4226},[641,642,905],[568,4228,4147],{"className":4229},[641,642,905],[568,4231,4155],{"className":4232},[641,642,905],[568,4234,4158],{"className":4235},[641,642,905],[568,4237,942],{"className":4238},[941],[568,4240,4242],{"className":4241},[885],[568,4243,4246],{"className":4244,"style":4245},[889],"height:0.15em;",[568,4247],{},[568,4249],{"className":4250,"style":648},[647],[568,4252,593],{"className":4253},[652],[568,4255],{"className":4256,"style":648},[647],[568,4258,4260,4263],{"className":4259},[632],[568,4261],{"className":4262,"style":865},[636],[568,4264,4266,4269,4334],{"className":4265},[641],[568,4267],{"className":4268},[872,873],[568,4270,4272],{"className":4271},[843],[568,4273,4275,4326],{"className":4274},[880,881],[568,4276,4278,4323],{"className":4277},[885],[568,4279,4281,4295,4303],{"className":4280,"style":890},[889],[568,4282,4283,4286],{"style":893},[568,4284],{"className":4285,"style":898},[897],[568,4287,4289],{"className":4288},[902,903,904,905],[568,4290,4292],{"className":4291},[641,905],[568,4293,4167],{"className":4294},[641,642,905],[568,4296,4297,4300],{"style":914},[568,4298],{"className":4299,"style":898},[897],[568,4301],{"className":4302,"style":922},[921],[568,4304,4305,4308],{"style":925},[568,4306],{"className":4307,"style":898},[897],[568,4309,4311],{"className":4310},[902,903,904,905],[568,4312,4314,4317,4320],{"className":4313},[641,905],[568,4315,4167],{"className":4316},[641,642,905],[568,4318,4170],{"className":4319},[1260,905],[568,4321,249],{"className":4322},[641,905],[568,4324,942],{"className":4325},[941],[568,4327,4329],{"className":4328},[885],[568,4330,4332],{"className":4331,"style":949},[889],[568,4333],{},[568,4335],{"className":4336},[955,873],"。耗时：只需 ",[568,4339,4341,4355],{"className":4340},[571],[568,4342,4344],{"className":4343},[575],[577,4345,4346],{"xmlns":579},[581,4347,4348,4353],{},[584,4349,4350],{},[587,4351,4352],{},"A",[620,4354,4352],{"encoding":622},[568,4356,4358],{"className":4357,"ariaHidden":628},[627],[568,4359,4361,4364],{"className":4360},[632],[568,4362],{"className":4363,"style":637},[636],[568,4365,4352],{"className":4366},[641,642],[33,4368,4369,1656,4372,4652,4653,701],{},[563,4370,4371],{},"缓存未命中，但命中内存的概率：",[568,4373,4375,4421],{"className":4374},[571],[568,4376,4378],{"className":4377},[575],[577,4379,4380],{"xmlns":579},[581,4381,4382,4418],{},[584,4383,4384,4396,4398,4404,4406],{},[4138,4385,4386,4388],{},[587,4387,4142],{},[584,4389,4390,4392,4394],{},[587,4391,600],{},[587,4393,4158],{},[587,4395,600],{},[591,4397,593],{},[843,4399,4400,4402],{},[595,4401,249],{},[587,4403,4167],{},[591,4405,1221],{},[843,4407,4408,4416],{},[584,4409,4410,4412,4414],{},[587,4411,600],{},[591,4413,4170],{},[595,4415,249],{},[587,4417,600],{},[620,4419,4420],{"encoding":622},"P_{mem} = \\frac{1}{n} \\times \\frac{m-1}{m}",[568,4422,4424,4489,4572],{"className":4423,"ariaHidden":628},[627],[568,4425,4427,4430,4480,4483,4486],{"className":4426},[632],[568,4428],{"className":4429,"style":4187},[636],[568,4431,4433,4436],{"className":4432},[641],[568,4434,4142],{"className":4435,"style":643},[641,642],[568,4437,4439],{"className":4438},[4197],[568,4440,4442,4472],{"className":4441},[880,881],[568,4443,4445,4469],{"className":4444},[885],[568,4446,4449],{"className":4447,"style":4448},[889],"height:0.1514em;",[568,4450,4451,4454],{"style":4210},[568,4452],{"className":4453,"style":4214},[897],[568,4455,4457],{"className":4456},[902,903,904,905],[568,4458,4460,4463,4466],{"className":4459},[641,905],[568,4461,600],{"className":4462},[641,642,905],[568,4464,4158],{"className":4465},[641,642,905],[568,4467,600],{"className":4468},[641,642,905],[568,4470,942],{"className":4471},[941],[568,4473,4475],{"className":4474},[885],[568,4476,4478],{"className":4477,"style":4245},[889],[568,4479],{},[568,4481],{"className":4482,"style":648},[647],[568,4484,593],{"className":4485},[652],[568,4487],{"className":4488,"style":648},[647],[568,4490,4492,4495,4563,4566,4569],{"className":4491},[632],[568,4493],{"className":4494,"style":865},[636],[568,4496,4498,4501,4560],{"className":4497},[641],[568,4499],{"className":4500},[872,873],[568,4502,4504],{"className":4503},[843],[568,4505,4507,4552],{"className":4506},[880,881],[568,4508,4510,4549],{"className":4509},[885],[568,4511,4513,4527,4535],{"className":4512,"style":890},[889],[568,4514,4515,4518],{"style":893},[568,4516],{"className":4517,"style":898},[897],[568,4519,4521],{"className":4520},[902,903,904,905],[568,4522,4524],{"className":4523},[641,905],[568,4525,4167],{"className":4526},[641,642,905],[568,4528,4529,4532],{"style":914},[568,4530],{"className":4531,"style":898},[897],[568,4533],{"className":4534,"style":922},[921],[568,4536,4537,4540],{"style":925},[568,4538],{"className":4539,"style":898},[897],[568,4541,4543],{"className":4542},[902,903,904,905],[568,4544,4546],{"className":4545},[641,905],[568,4547,249],{"className":4548},[641,905],[568,4550,942],{"className":4551},[941],[568,4553,4555],{"className":4554},[885],[568,4556,4558],{"className":4557,"style":949},[889],[568,4559],{},[568,4561],{"className":4562},[955,873],[568,4564],{"className":4565,"style":1256},[647],[568,4567,1221],{"className":4568},[1260],[568,4570],{"className":4571,"style":1256},[647],[568,4573,4575,4578],{"className":4574},[632],[568,4576],{"className":4577,"style":865},[636],[568,4579,4581,4584,4649],{"className":4580},[641],[568,4582],{"className":4583},[872,873],[568,4585,4587],{"className":4586},[843],[568,4588,4590,4641],{"className":4589},[880,881],[568,4591,4593,4638],{"className":4592},[885],[568,4594,4596,4610,4618],{"className":4595,"style":890},[889],[568,4597,4598,4601],{"style":893},[568,4599],{"className":4600,"style":898},[897],[568,4602,4604],{"className":4603},[902,903,904,905],[568,4605,4607],{"className":4606},[641,905],[568,4608,600],{"className":4609},[641,642,905],[568,4611,4612,4615],{"style":914},[568,4613],{"className":4614,"style":898},[897],[568,4616],{"className":4617,"style":922},[921],[568,4619,4620,4623],{"style":925},[568,4621],{"className":4622,"style":898},[897],[568,4624,4626],{"className":4625},[902,903,904,905],[568,4627,4629,4632,4635],{"className":4628},[641,905],[568,4630,600],{"className":4631},[641,642,905],[568,4633,4170],{"className":4634},[1260,905],[568,4636,249],{"className":4637},[641,905],[568,4639,942],{"className":4640},[941],[568,4642,4644],{"className":4643},[885],[568,4645,4647],{"className":4646,"style":949},[889],[568,4648],{},[568,4650],{"className":4651},[955,873],"。耗时：",[568,4654,4656,4675],{"className":4655},[571],[568,4657,4659],{"className":4658},[575],[577,4660,4661],{"xmlns":579},[581,4662,4663,4672],{},[584,4664,4665,4667,4669],{},[587,4666,4352],{},[591,4668,1508],{},[587,4670,4671],{},"B",[620,4673,4674],{"encoding":622},"A+B",[568,4676,4678,4697],{"className":4677,"ariaHidden":628},[627],[568,4679,4681,4685,4688,4691,4694],{"className":4680},[632],[568,4682],{"className":4683,"style":4684},[636],"height:0.7667em;vertical-align:-0.0833em;",[568,4686,4352],{"className":4687},[641,642],[568,4689],{"className":4690,"style":1256},[647],[568,4692,1508],{"className":4693},[1260],[568,4695],{"className":4696,"style":1256},[647],[568,4698,4700,4703],{"className":4699},[632],[568,4701],{"className":4702,"style":637},[636],[568,4704,4671],{"className":4705,"style":4706},[641,642],"margin-right:0.0502em;",[33,4708,4709,1656,4712,4652,5084,701],{},[563,4710,4711],{},"全未命中，在辅存中的概率：",[568,4713,4715,4772],{"className":4714},[571],[568,4716,4718],{"className":4717},[575],[577,4719,4720],{"xmlns":579},[581,4721,4722,4769],{},[584,4723,4724,4741,4743,4749,4751,4757,4759],{},[4138,4725,4726,4728],{},[587,4727,4142],{},[584,4729,4730,4733,4736,4738],{},[587,4731,4732],{},"d",[587,4734,4735],{},"i",[587,4737,603],{},[587,4739,4740],{},"k",[591,4742,593],{},[843,4744,4745,4747],{},[595,4746,249],{},[587,4748,4167],{},[591,4750,1221],{},[843,4752,4753,4755],{},[595,4754,249],{},[587,4756,600],{},[591,4758,593],{},[843,4760,4761,4763],{},[595,4762,249],{},[584,4764,4765,4767],{},[587,4766,4167],{},[587,4768,600],{},[620,4770,4771],{"encoding":622},"P_{disk} = \\frac{1}{n} \\times \\frac{1}{m} = \\frac{1}{nm}",[568,4773,4775,4843,4926,5009],{"className":4774,"ariaHidden":628},[627],[568,4776,4778,4781,4834,4837,4840],{"className":4777},[632],[568,4779],{"className":4780,"style":4187},[636],[568,4782,4784,4787],{"className":4783},[641],[568,4785,4142],{"className":4786,"style":643},[641,642],[568,4788,4790],{"className":4789},[4197],[568,4791,4793,4826],{"className":4792},[880,881],[568,4794,4796,4823],{"className":4795},[885],[568,4797,4799],{"className":4798,"style":4207},[889],[568,4800,4801,4804],{"style":4210},[568,4802],{"className":4803,"style":4214},[897],[568,4805,4807],{"className":4806},[902,903,904,905],[568,4808,4810,4813,4816,4819],{"className":4809},[641,905],[568,4811,4732],{"className":4812},[641,642,905],[568,4814,4735],{"className":4815},[641,642,905],[568,4817,603],{"className":4818},[641,642,905],[568,4820,4740],{"className":4821,"style":4822},[641,642,905],"margin-right:0.0315em;",[568,4824,942],{"className":4825},[941],[568,4827,4829],{"className":4828},[885],[568,4830,4832],{"className":4831,"style":4245},[889],[568,4833],{},[568,4835],{"className":4836,"style":648},[647],[568,4838,593],{"className":4839},[652],[568,4841],{"className":4842,"style":648},[647],[568,4844,4846,4849,4917,4920,4923],{"className":4845},[632],[568,4847],{"className":4848,"style":865},[636],[568,4850,4852,4855,4914],{"className":4851},[641],[568,4853],{"className":4854},[872,873],[568,4856,4858],{"className":4857},[843],[568,4859,4861,4906],{"className":4860},[880,881],[568,4862,4864,4903],{"className":4863},[885],[568,4865,4867,4881,4889],{"className":4866,"style":890},[889],[568,4868,4869,4872],{"style":893},[568,4870],{"className":4871,"style":898},[897],[568,4873,4875],{"className":4874},[902,903,904,905],[568,4876,4878],{"className":4877},[641,905],[568,4879,4167],{"className":4880},[641,642,905],[568,4882,4883,4886],{"style":914},[568,4884],{"className":4885,"style":898},[897],[568,4887],{"className":4888,"style":922},[921],[568,4890,4891,4894],{"style":925},[568,4892],{"className":4893,"style":898},[897],[568,4895,4897],{"className":4896},[902,903,904,905],[568,4898,4900],{"className":4899},[641,905],[568,4901,249],{"className":4902},[641,905],[568,4904,942],{"className":4905},[941],[568,4907,4909],{"className":4908},[885],[568,4910,4912],{"className":4911,"style":949},[889],[568,4913],{},[568,4915],{"className":4916},[955,873],[568,4918],{"className":4919,"style":1256},[647],[568,4921,1221],{"className":4922},[1260],[568,4924],{"className":4925,"style":1256},[647],[568,4927,4929,4932,5000,5003,5006],{"className":4928},[632],[568,4930],{"className":4931,"style":865},[636],[568,4933,4935,4938,4997],{"className":4934},[641],[568,4936],{"className":4937},[872,873],[568,4939,4941],{"className":4940},[843],[568,4942,4944,4989],{"className":4943},[880,881],[568,4945,4947,4986],{"className":4946},[885],[568,4948,4950,4964,4972],{"className":4949,"style":890},[889],[568,4951,4952,4955],{"style":893},[568,4953],{"className":4954,"style":898},[897],[568,4956,4958],{"className":4957},[902,903,904,905],[568,4959,4961],{"className":4960},[641,905],[568,4962,600],{"className":4963},[641,642,905],[568,4965,4966,4969],{"style":914},[568,4967],{"className":4968,"style":898},[897],[568,4970],{"className":4971,"style":922},[921],[568,4973,4974,4977],{"style":925},[568,4975],{"className":4976,"style":898},[897],[568,4978,4980],{"className":4979},[902,903,904,905],[568,4981,4983],{"className":4982},[641,905],[568,4984,249],{"className":4985},[641,905],[568,4987,942],{"className":4988},[941],[568,4990,4992],{"className":4991},[885],[568,4993,4995],{"className":4994,"style":949},[889],[568,4996],{},[568,4998],{"className":4999},[955,873],[568,5001],{"className":5002,"style":648},[647],[568,5004,593],{"className":5005},[652],[568,5007],{"className":5008,"style":648},[647],[568,5010,5012,5015],{"className":5011},[632],[568,5013],{"className":5014,"style":865},[636],[568,5016,5018,5021,5081],{"className":5017},[641],[568,5019],{"className":5020},[872,873],[568,5022,5024],{"className":5023},[843],[568,5025,5027,5073],{"className":5026},[880,881],[568,5028,5030,5070],{"className":5029},[885],[568,5031,5033,5048,5056],{"className":5032,"style":890},[889],[568,5034,5035,5038],{"style":893},[568,5036],{"className":5037,"style":898},[897],[568,5039,5041],{"className":5040},[902,903,904,905],[568,5042,5044],{"className":5043},[641,905],[568,5045,5047],{"className":5046},[641,642,905],"nm",[568,5049,5050,5053],{"style":914},[568,5051],{"className":5052,"style":898},[897],[568,5054],{"className":5055,"style":922},[921],[568,5057,5058,5061],{"style":925},[568,5059],{"className":5060,"style":898},[897],[568,5062,5064],{"className":5063},[902,903,904,905],[568,5065,5067],{"className":5066},[641,905],[568,5068,249],{"className":5069},[641,905],[568,5071,942],{"className":5072},[941],[568,5074,5076],{"className":5075},[885],[568,5077,5079],{"className":5078,"style":949},[889],[568,5080],{},[568,5082],{"className":5083},[955,873],[568,5085,5087,5110],{"className":5086},[571],[568,5088,5090],{"className":5089},[575],[577,5091,5092],{"xmlns":579},[581,5093,5094,5107],{},[584,5095,5096,5098,5100,5102,5104],{},[587,5097,4352],{},[591,5099,1508],{},[587,5101,4671],{},[591,5103,1508],{},[587,5105,5106],{},"C",[620,5108,5109],{"encoding":622},"A+B+C",[568,5111,5113,5131,5149],{"className":5112,"ariaHidden":628},[627],[568,5114,5116,5119,5122,5125,5128],{"className":5115},[632],[568,5117],{"className":5118,"style":4684},[636],[568,5120,4352],{"className":5121},[641,642],[568,5123],{"className":5124,"style":1256},[647],[568,5126,1508],{"className":5127},[1260],[568,5129],{"className":5130,"style":1256},[647],[568,5132,5134,5137,5140,5143,5146],{"className":5133},[632],[568,5135],{"className":5136,"style":4684},[636],[568,5138,4671],{"className":5139,"style":4706},[641,642],[568,5141],{"className":5142,"style":1256},[647],[568,5144,1508],{"className":5145},[1260],[568,5147],{"className":5148,"style":1256},[647],[568,5150,5152,5155],{"className":5151},[632],[568,5153],{"className":5154,"style":637},[636],[568,5156,5106],{"className":5157,"style":5158},[641,642],"margin-right:0.0715em;",[554,5160,3076],{"id":5161},"答案与详细解答-1",[26,5163,5164],{},[563,5165,5166],{},"(1) 数据所在层级的比率：",[30,5168,5169,5282,5399],{},[33,5170,5171,5172],{},"数据在缓存中的比率： ",[568,5173,5175,5199],{"className":5174},[571],[568,5176,5178],{"className":5177},[575],[577,5179,5180],{"xmlns":579},[581,5181,5182,5196],{},[584,5183,5184],{},[843,5185,5186,5194],{},[584,5187,5188,5190,5192],{},[587,5189,4167],{"mathvariant":2397},[591,5191,4170],{},[595,5193,249],{"mathvariant":2397},[587,5195,4167],{"mathvariant":2397},[620,5197,5198],{"encoding":622},"\\mathbf{\\frac{n-1}{n}}",[568,5200,5202],{"className":5201,"ariaHidden":628},[627],[568,5203,5205,5208],{"className":5204},[632],[568,5206],{"className":5207,"style":865},[636],[568,5209,5211,5214,5279],{"className":5210},[641],[568,5212],{"className":5213},[872,873],[568,5215,5217],{"className":5216},[843],[568,5218,5220,5271],{"className":5219},[880,881],[568,5221,5223,5268],{"className":5222},[885],[568,5224,5226,5240,5248],{"className":5225,"style":890},[889],[568,5227,5228,5231],{"style":893},[568,5229],{"className":5230,"style":898},[897],[568,5232,5234],{"className":5233},[902,903,904,905],[568,5235,5237],{"className":5236},[641,905],[568,5238,4167],{"className":5239},[641,2676,905],[568,5241,5242,5245],{"style":914},[568,5243],{"className":5244,"style":898},[897],[568,5246],{"className":5247,"style":922},[921],[568,5249,5250,5253],{"style":925},[568,5251],{"className":5252,"style":898},[897],[568,5254,5256],{"className":5255},[902,903,904,905],[568,5257,5259,5262,5265],{"className":5258},[641,905],[568,5260,4167],{"className":5261},[641,2676,905],[568,5263,4170],{"className":5264},[1260,905],[568,5266,249],{"className":5267},[641,2676,905],[568,5269,942],{"className":5270},[941],[568,5272,5274],{"className":5273},[885],[568,5275,5277],{"className":5276,"style":949},[889],[568,5278],{},[568,5280],{"className":5281},[955,873],[33,5283,5284,5285],{},"数据在内存（但不在缓存）中的比率： ",[568,5286,5288,5316],{"className":5287},[571],[568,5289,5291],{"className":5290},[575],[577,5292,5293],{"xmlns":579},[581,5294,5295,5313],{},[584,5296,5297],{},[843,5298,5299,5307],{},[584,5300,5301,5303,5305],{},[587,5302,600],{"mathvariant":2397},[591,5304,4170],{},[595,5306,249],{"mathvariant":2397},[584,5308,5309,5311],{},[587,5310,4167],{"mathvariant":2397},[587,5312,600],{"mathvariant":2397},[620,5314,5315],{"encoding":622},"\\mathbf{\\frac{m-1}{nm}}",[568,5317,5319],{"className":5318,"ariaHidden":628},[627],[568,5320,5322,5325],{"className":5321},[632],[568,5323],{"className":5324,"style":865},[636],[568,5326,5328,5331,5396],{"className":5327},[641],[568,5329],{"className":5330},[872,873],[568,5332,5334],{"className":5333},[843],[568,5335,5337,5388],{"className":5336},[880,881],[568,5338,5340,5385],{"className":5339},[885],[568,5341,5343,5357,5365],{"className":5342,"style":890},[889],[568,5344,5345,5348],{"style":893},[568,5346],{"className":5347,"style":898},[897],[568,5349,5351],{"className":5350},[902,903,904,905],[568,5352,5354],{"className":5353},[641,905],[568,5355,5047],{"className":5356},[641,2676,905],[568,5358,5359,5362],{"style":914},[568,5360],{"className":5361,"style":898},[897],[568,5363],{"className":5364,"style":922},[921],[568,5366,5367,5370],{"style":925},[568,5368],{"className":5369,"style":898},[897],[568,5371,5373],{"className":5372},[902,903,904,905],[568,5374,5376,5379,5382],{"className":5375},[641,905],[568,5377,600],{"className":5378},[641,2676,905],[568,5380,4170],{"className":5381},[1260,905],[568,5383,249],{"className":5384},[641,2676,905],[568,5386,942],{"className":5387},[941],[568,5389,5391],{"className":5390},[885],[568,5392,5394],{"className":5393,"style":949},[889],[568,5395],{},[568,5397],{"className":5398},[955,873],[33,5400,5401,5402],{},"数据在辅存（不在内存）中的比率： ",[568,5403,5405,5427],{"className":5404},[571],[568,5406,5408],{"className":5407},[575],[577,5409,5410],{"xmlns":579},[581,5411,5412,5424],{},[584,5413,5414],{},[843,5415,5416,5418],{},[595,5417,249],{"mathvariant":2397},[584,5419,5420,5422],{},[587,5421,4167],{"mathvariant":2397},[587,5423,600],{"mathvariant":2397},[620,5425,5426],{"encoding":622},"\\mathbf{\\frac{1}{nm}}",[568,5428,5430],{"className":5429,"ariaHidden":628},[627],[568,5431,5433,5436],{"className":5432},[632],[568,5434],{"className":5435,"style":865},[636],[568,5437,5439,5442,5501],{"className":5438},[641],[568,5440],{"className":5441},[872,873],[568,5443,5445],{"className":5444},[843],[568,5446,5448,5493],{"className":5447},[880,881],[568,5449,5451,5490],{"className":5450},[885],[568,5452,5454,5468,5476],{"className":5453,"style":890},[889],[568,5455,5456,5459],{"style":893},[568,5457],{"className":5458,"style":898},[897],[568,5460,5462],{"className":5461},[902,903,904,905],[568,5463,5465],{"className":5464},[641,905],[568,5466,5047],{"className":5467},[641,2676,905],[568,5469,5470,5473],{"style":914},[568,5471],{"className":5472,"style":898},[897],[568,5474],{"className":5475,"style":922},[921],[568,5477,5478,5481],{"style":925},[568,5479],{"className":5480,"style":898},[897],[568,5482,5484],{"className":5483},[902,903,904,905],[568,5485,5487],{"className":5486},[641,905],[568,5488,249],{"className":5489},[641,2676,905],[568,5491,942],{"className":5492},[941],[568,5494,5496],{"className":5495},[885],[568,5497,5499],{"className":5498,"style":949},[889],[568,5500],{},[568,5502],{"className":5503},[955,873],[26,5505,5506],{},[563,5507,5508],{},"(2) 平均访问时间 (EAT) 计算：",[26,5510,5511,4102],{},[568,5512,5514,5633],{"className":5513},[571],[568,5515,5517],{"className":5516},[575],[577,5518,5519],{"xmlns":579},[581,5520,5521,5630],{},[584,5522,5523,5526,5528,5530,5532,5544,5546,5548,5564,5566,5568,5570,5572,5574,5576,5586,5588,5590,5592,5594,5596,5598,5600,5602,5626],{},[587,5524,5525],{},"E",[587,5527,4352],{},[587,5529,589],{},[591,5531,593],{},[843,5533,5534,5542],{},[584,5535,5536,5538,5540],{},[587,5537,4167],{},[591,5539,4170],{},[595,5541,249],{},[587,5543,4167],{},[587,5545,4352],{},[591,5547,1508],{},[843,5549,5550,5558],{},[584,5551,5552,5554,5556],{},[587,5553,600],{},[591,5555,4170],{},[595,5557,249],{},[584,5559,5560,5562],{},[587,5561,4167],{},[587,5563,600],{},[591,5565,1062],{"stretchy":1061},[587,5567,4352],{},[591,5569,1508],{},[587,5571,4671],{},[591,5573,1071],{"stretchy":1061},[591,5575,1508],{},[843,5577,5578,5580],{},[595,5579,249],{},[584,5581,5582,5584],{},[587,5583,4167],{},[587,5585,600],{},[591,5587,1062],{"stretchy":1061},[587,5589,4352],{},[591,5591,1508],{},[587,5593,4671],{},[591,5595,1508],{},[587,5597,5106],{},[591,5599,1071],{"stretchy":1061},[591,5601,593],{},[584,5603,5604,5606,5608,5614,5616],{},[587,5605,4352],{"mathvariant":2397},[591,5607,1508],{},[843,5609,5610,5612],{},[587,5611,4671],{"mathvariant":2397},[587,5613,4167],{"mathvariant":2397},[591,5615,1508],{},[843,5617,5618,5620],{},[587,5619,5106],{"mathvariant":2397},[584,5621,5622,5624],{},[587,5623,4167],{"mathvariant":2397},[587,5625,600],{"mathvariant":2397},[5627,5628,5629],"mtext",{}," (ns)",[620,5631,5632],{"encoding":622},"EAT = \\frac{n-1}{n}A + \\frac{m-1}{nm}(A+B) + \\frac{1}{nm}(A+B+C) = \\mathbf{A + \\frac{B}{n} + \\frac{C}{nm}} \\text{ (ns)}",[568,5634,5636,5661,5753,5848,5869,5958,5976,5997],{"className":5635,"ariaHidden":628},[627],[568,5637,5639,5642,5646,5649,5652,5655,5658],{"className":5638},[632],[568,5640],{"className":5641,"style":637},[636],[568,5643,5525],{"className":5644,"style":5645},[641,642],"margin-right:0.0576em;",[568,5647,4352],{"className":5648},[641,642],[568,5650,589],{"className":5651,"style":643},[641,642],[568,5653],{"className":5654,"style":648},[647],[568,5656,593],{"className":5657},[652],[568,5659],{"className":5660,"style":648},[647],[568,5662,5664,5667,5741,5744,5747,5750],{"className":5663},[632],[568,5665],{"className":5666,"style":865},[636],[568,5668,5670,5673,5738],{"className":5669},[641],[568,5671],{"className":5672},[872,873],[568,5674,5676],{"className":5675},[843],[568,5677,5679,5730],{"className":5678},[880,881],[568,5680,5682,5727],{"className":5681},[885],[568,5683,5685,5699,5707],{"className":5684,"style":890},[889],[568,5686,5687,5690],{"style":893},[568,5688],{"className":5689,"style":898},[897],[568,5691,5693],{"className":5692},[902,903,904,905],[568,5694,5696],{"className":5695},[641,905],[568,5697,4167],{"className":5698},[641,642,905],[568,5700,5701,5704],{"style":914},[568,5702],{"className":5703,"style":898},[897],[568,5705],{"className":5706,"style":922},[921],[568,5708,5709,5712],{"style":925},[568,5710],{"className":5711,"style":898},[897],[568,5713,5715],{"className":5714},[902,903,904,905],[568,5716,5718,5721,5724],{"className":5717},[641,905],[568,5719,4167],{"className":5720},[641,642,905],[568,5722,4170],{"className":5723},[1260,905],[568,5725,249],{"className":5726},[641,905],[568,5728,942],{"className":5729},[941],[568,5731,5733],{"className":5732},[885],[568,5734,5736],{"className":5735,"style":949},[889],[568,5737],{},[568,5739],{"className":5740},[955,873],[568,5742,4352],{"className":5743},[641,642],[568,5745],{"className":5746,"style":1256},[647],[568,5748,1508],{"className":5749},[1260],[568,5751],{"className":5752,"style":1256},[647],[568,5754,5756,5759,5833,5836,5839,5842,5845],{"className":5755},[632],[568,5757],{"className":5758,"style":865},[636],[568,5760,5762,5765,5830],{"className":5761},[641],[568,5763],{"className":5764},[872,873],[568,5766,5768],{"className":5767},[843],[568,5769,5771,5822],{"className":5770},[880,881],[568,5772,5774,5819],{"className":5773},[885],[568,5775,5777,5791,5799],{"className":5776,"style":890},[889],[568,5778,5779,5782],{"style":893},[568,5780],{"className":5781,"style":898},[897],[568,5783,5785],{"className":5784},[902,903,904,905],[568,5786,5788],{"className":5787},[641,905],[568,5789,5047],{"className":5790},[641,642,905],[568,5792,5793,5796],{"style":914},[568,5794],{"className":5795,"style":898},[897],[568,5797],{"className":5798,"style":922},[921],[568,5800,5801,5804],{"style":925},[568,5802],{"className":5803,"style":898},[897],[568,5805,5807],{"className":5806},[902,903,904,905],[568,5808,5810,5813,5816],{"className":5809},[641,905],[568,5811,600],{"className":5812},[641,642,905],[568,5814,4170],{"className":5815},[1260,905],[568,5817,249],{"className":5818},[641,905],[568,5820,942],{"className":5821},[941],[568,5823,5825],{"className":5824},[885],[568,5826,5828],{"className":5827,"style":949},[889],[568,5829],{},[568,5831],{"className":5832},[955,873],[568,5834,1062],{"className":5835},[872],[568,5837,4352],{"className":5838},[641,642],[568,5840],{"className":5841,"style":1256},[647],[568,5843,1508],{"className":5844},[1260],[568,5846],{"className":5847,"style":1256},[647],[568,5849,5851,5854,5857,5860,5863,5866],{"className":5850},[632],[568,5852],{"className":5853,"style":662},[636],[568,5855,4671],{"className":5856,"style":4706},[641,642],[568,5858,1071],{"className":5859},[955],[568,5861],{"className":5862,"style":1256},[647],[568,5864,1508],{"className":5865},[1260],[568,5867],{"className":5868,"style":1256},[647],[568,5870,5872,5875,5943,5946,5949,5952,5955],{"className":5871},[632],[568,5873],{"className":5874,"style":865},[636],[568,5876,5878,5881,5940],{"className":5877},[641],[568,5879],{"className":5880},[872,873],[568,5882,5884],{"className":5883},[843],[568,5885,5887,5932],{"className":5886},[880,881],[568,5888,5890,5929],{"className":5889},[885],[568,5891,5893,5907,5915],{"className":5892,"style":890},[889],[568,5894,5895,5898],{"style":893},[568,5896],{"className":5897,"style":898},[897],[568,5899,5901],{"className":5900},[902,903,904,905],[568,5902,5904],{"className":5903},[641,905],[568,5905,5047],{"className":5906},[641,642,905],[568,5908,5909,5912],{"style":914},[568,5910],{"className":5911,"style":898},[897],[568,5913],{"className":5914,"style":922},[921],[568,5916,5917,5920],{"style":925},[568,5918],{"className":5919,"style":898},[897],[568,5921,5923],{"className":5922},[902,903,904,905],[568,5924,5926],{"className":5925},[641,905],[568,5927,249],{"className":5928},[641,905],[568,5930,942],{"className":5931},[941],[568,5933,5935],{"className":5934},[885],[568,5936,5938],{"className":5937,"style":949},[889],[568,5939],{},[568,5941],{"className":5942},[955,873],[568,5944,1062],{"className":5945},[872],[568,5947,4352],{"className":5948},[641,642],[568,5950],{"className":5951,"style":1256},[647],[568,5953,1508],{"className":5954},[1260],[568,5956],{"className":5957,"style":1256},[647],[568,5959,5961,5964,5967,5970,5973],{"className":5960},[632],[568,5962],{"className":5963,"style":4684},[636],[568,5965,4671],{"className":5966,"style":4706},[641,642],[568,5968],{"className":5969,"style":1256},[647],[568,5971,1508],{"className":5972},[1260],[568,5974],{"className":5975,"style":1256},[647],[568,5977,5979,5982,5985,5988,5991,5994],{"className":5978},[632],[568,5980],{"className":5981,"style":662},[636],[568,5983,5106],{"className":5984,"style":5158},[641,642],[568,5986,1071],{"className":5987},[955],[568,5989],{"className":5990,"style":648},[647],[568,5992,593],{"className":5993},[652],[568,5995],{"className":5996,"style":648},[647],[568,5998,6000,6004,6165],{"className":5999},[632],[568,6001],{"className":6002,"style":6003},[636],"height:1.2193em;vertical-align:-0.345em;",[568,6005,6007,6010,6013,6016,6019,6088,6091,6094,6097],{"className":6006},[641],[568,6008,4352],{"className":6009},[641,2676],[568,6011],{"className":6012,"style":1256},[647],[568,6014,1508],{"className":6015},[1260],[568,6017],{"className":6018,"style":1256},[647],[568,6020,6022,6025,6085],{"className":6021},[641],[568,6023],{"className":6024},[872,873],[568,6026,6028],{"className":6027},[843],[568,6029,6031,6077],{"className":6030},[880,881],[568,6032,6034,6074],{"className":6033},[885],[568,6035,6038,6052,6060],{"className":6036,"style":6037},[889],"height:0.8743em;",[568,6039,6040,6043],{"style":893},[568,6041],{"className":6042,"style":898},[897],[568,6044,6046],{"className":6045},[902,903,904,905],[568,6047,6049],{"className":6048},[641,905],[568,6050,4167],{"className":6051},[641,2676,905],[568,6053,6054,6057],{"style":914},[568,6055],{"className":6056,"style":898},[897],[568,6058],{"className":6059,"style":922},[921],[568,6061,6062,6065],{"style":925},[568,6063],{"className":6064,"style":898},[897],[568,6066,6068],{"className":6067},[902,903,904,905],[568,6069,6071],{"className":6070},[641,905],[568,6072,4671],{"className":6073},[641,2676,905],[568,6075,942],{"className":6076},[941],[568,6078,6080],{"className":6079},[885],[568,6081,6083],{"className":6082,"style":949},[889],[568,6084],{},[568,6086],{"className":6087},[955,873],[568,6089],{"className":6090,"style":1256},[647],[568,6092,1508],{"className":6093},[1260],[568,6095],{"className":6096,"style":1256},[647],[568,6098,6100,6103,6162],{"className":6099},[641],[568,6101],{"className":6102},[872,873],[568,6104,6106],{"className":6105},[843],[568,6107,6109,6154],{"className":6108},[880,881],[568,6110,6112,6151],{"className":6111},[885],[568,6113,6115,6129,6137],{"className":6114,"style":6037},[889],[568,6116,6117,6120],{"style":893},[568,6118],{"className":6119,"style":898},[897],[568,6121,6123],{"className":6122},[902,903,904,905],[568,6124,6126],{"className":6125},[641,905],[568,6127,5047],{"className":6128},[641,2676,905],[568,6130,6131,6134],{"style":914},[568,6132],{"className":6133,"style":898},[897],[568,6135],{"className":6136,"style":922},[921],[568,6138,6139,6142],{"style":925},[568,6140],{"className":6141,"style":898},[897],[568,6143,6145],{"className":6144},[902,903,904,905],[568,6146,6148],{"className":6147},[641,905],[568,6149,5106],{"className":6150},[641,2676,905],[568,6152,942],{"className":6153},[941],[568,6155,6157],{"className":6156},[885],[568,6158,6160],{"className":6159,"style":949},[889],[568,6161],{},[568,6163],{"className":6164},[955,873],[568,6166,6169],{"className":6167},[641,6168],"text",[568,6170,5629],{"className":6171},[641],[13,6173,6175],{"id":6174},"_18-磁盘组柱面数总容量与平均等待时间","18. 磁盘组柱面数、总容量与平均等待时间",[26,6177,6178],{},"某磁盘组有 6 片盘片，每片有两个记录面，存储区域内径为 22cm，外径为 33cm，道存储密度为 40 道\u002Fcm，内层位存储密度为 400b\u002Fcm，转速为 3000r\u002Fmin（转\u002F分），问共有多少柱面？盘组总存储量为多少？平均等待时间为多少？",[26,6180,41],{},[554,6182,3076],{"id":6183},"答案与详细解答-2",[30,6185,6186,6456,6922],{},[33,6187,6188,6191,6192,6336,6337,701],{},[563,6189,6190],{},"柱面数：","\n有效半径范围 = ",[568,6193,6195,6229],{"className":6194},[571],[568,6196,6198],{"className":6197},[575],[577,6199,6200],{"xmlns":579},[581,6201,6202,6226],{},[584,6203,6204,6218,6220,6223],{},[843,6205,6206,6216],{},[584,6207,6208,6211,6213],{},[595,6209,6210],{},"33",[591,6212,4170],{},[595,6214,6215],{},"22",[595,6217,268],{},[591,6219,593],{},[595,6221,6222],{},"5.5",[5627,6224,6225],{}," cm",[620,6227,6228],{"encoding":622},"\\frac{33 - 22}{2} = 5.5 \\text{ cm}",[568,6230,6232,6321],{"className":6231,"ariaHidden":628},[627],[568,6233,6235,6238,6312,6315,6318],{"className":6234},[632],[568,6236],{"className":6237,"style":865},[636],[568,6239,6241,6244,6309],{"className":6240},[641],[568,6242],{"className":6243},[872,873],[568,6245,6247],{"className":6246},[843],[568,6248,6250,6301],{"className":6249},[880,881],[568,6251,6253,6298],{"className":6252},[885],[568,6254,6256,6270,6278],{"className":6255,"style":890},[889],[568,6257,6258,6261],{"style":893},[568,6259],{"className":6260,"style":898},[897],[568,6262,6264],{"className":6263},[902,903,904,905],[568,6265,6267],{"className":6266},[641,905],[568,6268,268],{"className":6269},[641,905],[568,6271,6272,6275],{"style":914},[568,6273],{"className":6274,"style":898},[897],[568,6276],{"className":6277,"style":922},[921],[568,6279,6280,6283],{"style":925},[568,6281],{"className":6282,"style":898},[897],[568,6284,6286],{"className":6285},[902,903,904,905],[568,6287,6289,6292,6295],{"className":6288},[641,905],[568,6290,6210],{"className":6291},[641,905],[568,6293,4170],{"className":6294},[1260,905],[568,6296,6215],{"className":6297},[641,905],[568,6299,942],{"className":6300},[941],[568,6302,6304],{"className":6303},[885],[568,6305,6307],{"className":6306,"style":949},[889],[568,6308],{},[568,6310],{"className":6311},[955,873],[568,6313],{"className":6314,"style":648},[647],[568,6316,593],{"className":6317},[652],[568,6319],{"className":6320,"style":648},[647],[568,6322,6324,6327,6330],{"className":6323},[632],[568,6325],{"className":6326,"style":691},[636],[568,6328,6222],{"className":6329},[641],[568,6331,6333],{"className":6332},[641,6168],[568,6334,6225],{"className":6335},[641],"\n柱面数 = ",[568,6338,6340,6373],{"className":6339},[571],[568,6341,6343],{"className":6342},[575],[577,6344,6345],{"xmlns":579},[581,6346,6347,6370],{},[584,6348,6349,6351,6353,6355,6357,6360,6362],{},[595,6350,6222],{},[5627,6352,6225],{},[591,6354,1221],{},[595,6356,1703],{},[5627,6358,6359],{}," 道\u002Fcm",[591,6361,593],{},[584,6363,6364,6367],{},[595,6365,6366],{"mathvariant":2397},"220",[5627,6368,6369],{}," 柱面",[620,6371,6372],{"encoding":622},"5.5 \\text{ cm} \\times 40 \\text{ 道\u002Fcm} = \\mathbf{220 \\text{ 柱面}}",[568,6374,6376,6400,6434],{"className":6375,"ariaHidden":628},[627],[568,6377,6379,6382,6385,6391,6394,6397],{"className":6378},[632],[568,6380],{"className":6381,"style":1249},[636],[568,6383,6222],{"className":6384},[641],[568,6386,6388],{"className":6387},[641,6168],[568,6389,6225],{"className":6390},[641],[568,6392],{"className":6393,"style":1256},[647],[568,6395,1221],{"className":6396},[1260],[568,6398],{"className":6399,"style":1256},[647],[568,6401,6403,6406,6409,6425,6428,6431],{"className":6402},[632],[568,6404],{"className":6405,"style":662},[636],[568,6407,1703],{"className":6408},[641],[568,6410,6412,6416,6421],{"className":6411},[641,6168],[568,6413,6415],{"className":6414},[641]," ",[568,6417,6420],{"className":6418},[641,6419],"cjk_fallback","道",[568,6422,6424],{"className":6423},[641],"\u002Fcm",[568,6426],{"className":6427,"style":648},[647],[568,6429,593],{"className":6430},[652],[568,6432],{"className":6433,"style":648},[647],[568,6435,6437,6440],{"className":6436},[632],[568,6438],{"className":6439,"style":637},[636],[568,6441,6443,6446],{"className":6442},[641],[568,6444,6366],{"className":6445},[641,2676],[568,6447,6449,6452],{"className":6448},[641,6168],[568,6450,6415],{"className":6451},[641],[568,6453,6455],{"className":6454},[641,6419],"柱面",[33,6457,6458,6461,6462,6524,6525,6637,6638,6667,6668,6696,6697,1656,6725,6759,6760,6835,6836,6878,6879,6921],{},[563,6459,6460],{},"总存储量：","\n最内层磁道周长 = ",[568,6463,6465,6486],{"className":6464},[571],[568,6466,6468],{"className":6467},[575],[577,6469,6470],{"xmlns":579},[581,6471,6472,6483],{},[584,6473,6474,6477,6479,6481],{},[587,6475,6476],{},"π",[591,6478,1221],{},[595,6480,6215],{},[5627,6482,6225],{},[620,6484,6485],{"encoding":622},"\\pi \\times 22 \\text{ cm}",[568,6487,6489,6509],{"className":6488,"ariaHidden":628},[627],[568,6490,6492,6496,6500,6503,6506],{"className":6491},[632],[568,6493],{"className":6494,"style":6495},[636],"height:0.6667em;vertical-align:-0.0833em;",[568,6497,6476],{"className":6498,"style":6499},[641,642],"margin-right:0.0359em;",[568,6501],{"className":6502,"style":1256},[647],[568,6504,1221],{"className":6505},[1260],[568,6507],{"className":6508,"style":1256},[647],[568,6510,6512,6515,6518],{"className":6511},[632],[568,6513],{"className":6514,"style":691},[636],[568,6516,6215],{"className":6517},[641],[568,6519,6521],{"className":6520},[641,6168],[568,6522,6225],{"className":6523},[641],"\n每条磁道容量 = ",[568,6526,6528,6564],{"className":6527},[571],[568,6529,6531],{"className":6530},[575],[577,6532,6533],{"xmlns":579},[581,6534,6535,6561],{},[584,6536,6537,6539,6541,6543,6545,6548,6551,6553,6556,6558],{},[595,6538,6215],{},[587,6540,6476],{},[5627,6542,6225],{},[591,6544,1221],{},[595,6546,6547],{},"400",[5627,6549,6550],{}," b\u002Fcm",[591,6552,593],{},[595,6554,6555],{},"8800",[587,6557,6476],{},[5627,6559,6560],{}," bits",[620,6562,6563],{"encoding":622},"22\\pi \\text{ cm} \\times 400 \\text{ b\u002Fcm} = 8800\\pi \\text{ bits}",[568,6565,6567,6594,6618],{"className":6566,"ariaHidden":628},[627],[568,6568,6570,6573,6576,6579,6585,6588,6591],{"className":6569},[632],[568,6571],{"className":6572,"style":1249},[636],[568,6574,6215],{"className":6575},[641],[568,6577,6476],{"className":6578,"style":6499},[641,642],[568,6580,6582],{"className":6581},[641,6168],[568,6583,6225],{"className":6584},[641],[568,6586],{"className":6587,"style":1256},[647],[568,6589,1221],{"className":6590},[1260],[568,6592],{"className":6593,"style":1256},[647],[568,6595,6597,6600,6603,6609,6612,6615],{"className":6596},[632],[568,6598],{"className":6599,"style":662},[636],[568,6601,6547],{"className":6602},[641],[568,6604,6606],{"className":6605},[641,6168],[568,6607,6550],{"className":6608},[641],[568,6610],{"className":6611,"style":648},[647],[568,6613,593],{"className":6614},[652],[568,6616],{"className":6617,"style":648},[647],[568,6619,6621,6625,6628,6631],{"className":6620},[632],[568,6622],{"className":6623,"style":6624},[636],"height:0.6944em;",[568,6626,6555],{"className":6627},[641],[568,6629,6476],{"className":6630,"style":6499},[641,642],[568,6632,6634],{"className":6633},[641,6168],[568,6635,6560],{"className":6636},[641],"。\n总磁头\u002F盘面数 = 6片 ",[568,6639,6641,6655],{"className":6640},[571],[568,6642,6644],{"className":6643},[575],[577,6645,6646],{"xmlns":579},[581,6647,6648,6652],{},[584,6649,6650],{},[591,6651,1221],{},[620,6653,6654],{"encoding":622},"\\times",[568,6656,6658],{"className":6657,"ariaHidden":628},[627],[568,6659,6661,6664],{"className":6660},[632],[568,6662],{"className":6663,"style":6495},[636],[568,6665,1221],{"className":6666},[641]," 2面 = 12面。\n总容量 = 12面 ",[568,6669,6671,6684],{"className":6670},[571],[568,6672,6674],{"className":6673},[575],[577,6675,6676],{"xmlns":579},[581,6677,6678,6682],{},[584,6679,6680],{},[591,6681,1221],{},[620,6683,6654],{"encoding":622},[568,6685,6687],{"className":6686,"ariaHidden":628},[627],[568,6688,6690,6693],{"className":6689},[632],[568,6691],{"className":6692,"style":6495},[636],[568,6694,1221],{"className":6695},[641]," 220道 ",[568,6698,6700,6713],{"className":6699},[571],[568,6701,6703],{"className":6702},[575],[577,6704,6705],{"xmlns":579},[581,6706,6707,6711],{},[584,6708,6709],{},[591,6710,1221],{},[620,6712,6654],{"encoding":622},[568,6714,6716],{"className":6715,"ariaHidden":628},[627],[568,6717,6719,6722],{"className":6718},[632],[568,6720],{"className":6721,"style":6495},[636],[568,6723,1221],{"className":6724},[641],[568,6726,6728,6744],{"className":6727},[571],[568,6729,6731],{"className":6730},[575],[577,6732,6733],{"xmlns":579},[581,6734,6735,6741],{},[584,6736,6737,6739],{},[595,6738,6555],{},[587,6740,6476],{},[620,6742,6743],{"encoding":622},"8800\\pi",[568,6745,6747],{"className":6746,"ariaHidden":628},[627],[568,6748,6750,6753,6756],{"className":6749},[632],[568,6751],{"className":6752,"style":691},[636],[568,6754,6555],{"className":6755},[641],[568,6757,6476],{"className":6758,"style":6499},[641,642]," bits = ",[568,6761,6763,6793],{"className":6762},[571],[568,6764,6766],{"className":6765},[575],[577,6767,6768],{"xmlns":579},[581,6769,6770,6790],{},[584,6771,6772,6775,6778,6781,6783,6786,6788],{},[595,6773,6774],{},"23",[591,6776,6777],{"separator":628},",",[595,6779,6780],{},"232",[591,6782,6777],{"separator":628},[595,6784,6785],{},"000",[587,6787,6476],{},[5627,6789,6560],{},[620,6791,6792],{"encoding":622},"23,232,000 \\pi \\text{ bits}",[568,6794,6796],{"className":6795,"ariaHidden":628},[627],[568,6797,6799,6803,6806,6810,6814,6817,6820,6823,6826,6829],{"className":6798},[632],[568,6800],{"className":6801,"style":6802},[636],"height:0.8889em;vertical-align:-0.1944em;",[568,6804,6774],{"className":6805},[641],[568,6807,6777],{"className":6808},[6809],"mpunct",[568,6811],{"className":6812,"style":6813},[647],"margin-right:0.1667em;",[568,6815,6780],{"className":6816},[641],[568,6818,6777],{"className":6819},[6809],[568,6821],{"className":6822,"style":6813},[647],[568,6824,6785],{"className":6825},[641],[568,6827,6476],{"className":6828,"style":6499},[641,642],[568,6830,6832],{"className":6831},[641,6168],[568,6833,6560],{"className":6834},[641]," （约 ",[568,6837,6839,6857],{"className":6838},[571],[568,6840,6842],{"className":6841},[575],[577,6843,6844],{"xmlns":579},[581,6845,6846,6854],{},[584,6847,6848,6851],{},[595,6849,6850],{"mathvariant":2397},"72.98",[5627,6852,6853],{}," Mbits",[620,6855,6856],{"encoding":622},"\\mathbf{72.98 \\text{ Mbits}}",[568,6858,6860],{"className":6859,"ariaHidden":628},[627],[568,6861,6863,6866],{"className":6862},[632],[568,6864],{"className":6865,"style":6624},[636],[568,6867,6869,6872],{"className":6868},[641],[568,6870,6850],{"className":6871},[641,2676],[568,6873,6875],{"className":6874},[641,6168],[568,6876,6853],{"className":6877},[641]," 或 ",[568,6880,6882,6900],{"className":6881},[571],[568,6883,6885],{"className":6884},[575],[577,6886,6887],{"xmlns":579},[581,6888,6889,6897],{},[584,6890,6891,6894],{},[595,6892,6893],{"mathvariant":2397},"9.12",[5627,6895,6896],{}," MB",[620,6898,6899],{"encoding":622},"\\mathbf{9.12 \\text{ MB}}",[568,6901,6903],{"className":6902,"ariaHidden":628},[627],[568,6904,6906,6909],{"className":6905},[632],[568,6907],{"className":6908,"style":637},[636],[568,6910,6912,6915],{"className":6911},[641],[568,6913,6893],{"className":6914},[641,2676],[568,6916,6918],{"className":6917},[641,6168],[568,6919,6896],{"className":6920},[641],"）。",[33,6923,6924,6927,6928,6994,6995,3448],{},[563,6925,6926],{},"平均等待时间：","\n转速 = 3000 r\u002Fmin = 50 r\u002Fs。旋转一圈需 ",[568,6929,6931,6957],{"className":6930},[571],[568,6932,6934],{"className":6933},[575],[577,6935,6936],{"xmlns":579},[581,6937,6938,6954],{},[584,6939,6940,6942,6944,6946,6948,6950,6952],{},[595,6941,597],{},[587,6943,607],{"mathvariant":606},[595,6945,255],{},[591,6947,593],{},[595,6949,293],{},[587,6951,600],{},[587,6953,603],{},[620,6955,6956],{"encoding":622},"1000 \u002F 50 = 20 ms",[568,6958,6960,6979],{"className":6959,"ariaHidden":628},[627],[568,6961,6963,6966,6970,6973,6976],{"className":6962},[632],[568,6964],{"className":6965,"style":662},[636],[568,6967,6969],{"className":6968},[641],"1000\u002F50",[568,6971],{"className":6972,"style":648},[647],[568,6974,593],{"className":6975},[652],[568,6977],{"className":6978,"style":648},[647],[568,6980,6982,6985,6988,6991],{"className":6981},[632],[568,6983],{"className":6984,"style":691},[636],[568,6986,293],{"className":6987},[641],[568,6989,600],{"className":6990},[641,642],[568,6992,603],{"className":6993},[641,642],"。\n平均等待时间 = ",[568,6996,6998,7034],{"className":6997},[571],[568,6999,7001],{"className":7000},[575],[577,7002,7003],{"xmlns":579},[581,7004,7005,7031],{},[584,7006,7007,7013,7015,7017,7019,7021,7023],{},[843,7008,7009,7011],{},[595,7010,249],{},[595,7012,268],{},[591,7014,1221],{},[595,7016,293],{},[587,7018,600],{},[587,7020,603],{},[591,7022,593],{},[584,7024,7025,7027,7029],{},[595,7026,330],{"mathvariant":2397},[587,7028,600],{"mathvariant":2397},[587,7030,603],{"mathvariant":2397},[620,7032,7033],{"encoding":622},"\\frac{1}{2} \\times 20ms = \\mathbf{10 ms}",[568,7035,7037,7120,7144],{"className":7036,"ariaHidden":628},[627],[568,7038,7040,7043,7111,7114,7117],{"className":7039},[632],[568,7041],{"className":7042,"style":865},[636],[568,7044,7046,7049,7108],{"className":7045},[641],[568,7047],{"className":7048},[872,873],[568,7050,7052],{"className":7051},[843],[568,7053,7055,7100],{"className":7054},[880,881],[568,7056,7058,7097],{"className":7057},[885],[568,7059,7061,7075,7083],{"className":7060,"style":890},[889],[568,7062,7063,7066],{"style":893},[568,7064],{"className":7065,"style":898},[897],[568,7067,7069],{"className":7068},[902,903,904,905],[568,7070,7072],{"className":7071},[641,905],[568,7073,268],{"className":7074},[641,905],[568,7076,7077,7080],{"style":914},[568,7078],{"className":7079,"style":898},[897],[568,7081],{"className":7082,"style":922},[921],[568,7084,7085,7088],{"style":925},[568,7086],{"className":7087,"style":898},[897],[568,7089,7091],{"className":7090},[902,903,904,905],[568,7092,7094],{"className":7093},[641,905],[568,7095,249],{"className":7096},[641,905],[568,7098,942],{"className":7099},[941],[568,7101,7103],{"className":7102},[885],[568,7104,7106],{"className":7105,"style":949},[889],[568,7107],{},[568,7109],{"className":7110},[955,873],[568,7112],{"className":7113,"style":1256},[647],[568,7115,1221],{"className":7116},[1260],[568,7118],{"className":7119,"style":1256},[647],[568,7121,7123,7126,7129,7132,7135,7138,7141],{"className":7122},[632],[568,7124],{"className":7125,"style":691},[636],[568,7127,293],{"className":7128},[641],[568,7130,600],{"className":7131},[641,642],[568,7133,603],{"className":7134},[641,642],[568,7136],{"className":7137,"style":648},[647],[568,7139,593],{"className":7140},[652],[568,7142],{"className":7143,"style":648},[647],[568,7145,7147,7150],{"className":7146},[632],[568,7148],{"className":7149,"style":691},[636],[568,7151,7153],{"className":7152},[641],[568,7154,7156],{"className":7155},[641,2676],"10ms",[13,7158,7160],{"id":7159},"_19-四道作业系统sjf-抢占式优先数调度","19. 四道作业系统：SJF + 抢占式优先数调度",[26,7162,7163],{},"若有一个四道作业系统，如果在一段时间内先后有 6 个作业，它们提交和运行时间由下表给出。作业采用短作业优先的调度算法，进程采用以优先数的抢占式调度算法，作业优先数就是进程优先数，优先数越小，优先级越高。",[53,7165,7166,7187],{},[56,7167,7168],{},[59,7169,7170,7172,7174,7176,7179,7181,7183,7185],{},[62,7171,224],{"align":64},[62,7173,227],{"align":64},[62,7175,230],{"align":64},[62,7177,7178],{"align":64},"优先数",[62,7180,233],{"align":64},[62,7182,236],{"align":64},[62,7184,239],{"align":64},[62,7186,242],{"align":64},[73,7188,7189,7207,7225,7243,7261,7279],{},[59,7190,7191,7193,7195,7197,7199,7201,7203,7205],{},[78,7192,249],{"align":64},[78,7194,252],{"align":64},[78,7196,1703],{"align":64},[78,7198,324],{"align":64},[78,7200],{"align":64},[78,7202],{"align":64},[78,7204],{"align":64},[78,7206],{"align":64},[59,7208,7209,7211,7213,7215,7217,7219,7221,7223],{},[78,7210,268],{"align":64},[78,7212,271],{"align":64},[78,7214,274],{"align":64},[78,7216,306],{"align":64},[78,7218],{"align":64},[78,7220],{"align":64},[78,7222],{"align":64},[78,7224],{"align":64},[59,7226,7227,7229,7231,7233,7235,7237,7239,7241],{},[78,7228,287],{"align":64},[78,7230,290],{"align":64},[78,7232,293],{"align":64},[78,7234,268],{"align":64},[78,7236],{"align":64},[78,7238],{"align":64},[78,7240],{"align":64},[78,7242],{"align":64},[59,7244,7245,7247,7249,7251,7253,7255,7257,7259],{},[78,7246,306],{"align":64},[78,7248,309],{"align":64},[78,7250,293],{"align":64},[78,7252,287],{"align":64},[78,7254],{"align":64},[78,7256],{"align":64},[78,7258],{"align":64},[78,7260],{"align":64},[59,7262,7263,7265,7267,7269,7271,7273,7275,7277],{},[78,7264,324],{"align":64},[78,7266,327],{"align":64},[78,7268,330],{"align":64},[78,7270,268],{"align":64},[78,7272],{"align":64},[78,7274],{"align":64},[78,7276],{"align":64},[78,7278],{"align":64},[59,7280,7281,7283,7285,7287,7289,7291,7293,7295],{},[78,7282,343],{"align":64},[78,7284,346],{"align":64},[78,7286,324],{"align":64},[78,7288,268],{"align":64},[78,7290],{"align":64},[78,7292],{"align":64},[78,7294],{"align":64},[78,7296],{"align":64},[26,7298,359],{},[30,7300,7301,7303],{},[33,7302,364],{},[33,7304,367],{},[26,7306,41],{},[554,7308,823],{"id":7309},"原理解析-the-why-3",[30,7311,7312,7318],{},[33,7313,7314,7317],{},[563,7315,7316],{},"\"四道\"作业系统："," 意味着内存中最多只能同时存在 4 个进程。如果有第 5 个作业到达，哪怕它是极短的作业，也必须在\"外存后备队列\"中排队，直到内存有人腾出位置！",[33,7319,7320,7323],{},[563,7321,7322],{},"双层调度："," 高级调度（进内存）看 SJF；低级调度（抢 CPU）看 优先数。",[554,7325,3076],{"id":7326},"答案与详细解答-3",[26,7328,7329],{},[563,7330,7331],{},"(1) 时间表格计算",[53,7333,7334,7358],{},[56,7335,7336],{},[59,7337,7338,7341,7343,7346,7349,7351,7354,7356],{},[62,7339,7340],{"align":64},"作业",[62,7342,227],{"align":64},[62,7344,7345],{"align":64},"运行时间",[62,7347,7348],{"align":64},"优先",[62,7350,233],{"align":64},[62,7352,7353],{"align":64},"完成时间",[62,7355,239],{"align":64},[62,7357,242],{"align":64},[73,7359,7360,7383,7406,7428,7451,7474],{},[59,7361,7362,7366,7368,7370,7372,7374,7377,7380],{},[78,7363,7364],{"align":64},[563,7365,249],{},[78,7367,252],{"align":64},[78,7369,1703],{"align":64},[78,7371,324],{"align":64},[78,7373,252],{"align":64},[78,7375,7376],{"align":64},"10:05",[78,7378,7379],{"align":64},"125",[78,7381,7382],{"align":64},"125\u002F40 = 3.125",[59,7384,7385,7389,7391,7393,7395,7397,7400,7403],{},[78,7386,7387],{"align":64},[563,7388,268],{},[78,7390,271],{"align":64},[78,7392,274],{"align":64},[78,7394,306],{"align":64},[78,7396,271],{"align":64},[78,7398,7399],{"align":64},"9:40",[78,7401,7402],{"align":64},"85",[78,7404,7405],{"align":64},"85\u002F30 ≈ 2.833",[59,7407,7408,7412,7414,7416,7418,7420,7423,7425],{},[78,7409,7410],{"align":64},[563,7411,287],{},[78,7413,290],{"align":64},[78,7415,293],{"align":64},[78,7417,268],{"align":64},[78,7419,290],{"align":64},[78,7421,7422],{"align":64},"8:40",[78,7424,293],{"align":64},[78,7426,7427],{"align":64},"20\u002F20 = 1.0",[59,7429,7430,7434,7436,7438,7440,7443,7446,7448],{},[78,7431,7432],{"align":64},[563,7433,306],{},[78,7435,309],{"align":64},[78,7437,293],{"align":64},[78,7439,287],{"align":64},[78,7441,7442],{"align":64},"8:55",[78,7444,7445],{"align":64},"9:15",[78,7447,255],{"align":64},[78,7449,7450],{"align":64},"50\u002F20 = 2.5",[59,7452,7453,7457,7459,7461,7463,7466,7468,7471],{},[78,7454,7455],{"align":64},[563,7456,324],{},[78,7458,327],{"align":64},[78,7460,330],{"align":64},[78,7462,268],{"align":64},[78,7464,7465],{"align":64},"8:45",[78,7467,7442],{"align":64},[78,7469,7470],{"align":64},"25",[78,7472,7473],{"align":64},"25\u002F10 = 2.5",[59,7475,7476,7480,7482,7484,7486,7488,7490,7492],{},[78,7477,7478],{"align":64},[563,7479,343],{},[78,7481,346],{"align":64},[78,7483,324],{"align":64},[78,7485,268],{"align":64},[78,7487,7422],{"align":64},[78,7489,7465],{"align":64},[78,7491,330],{"align":64},[78,7493,7494],{"align":64},"10\u002F5 = 2.0",[26,7496,7497],{},[563,7498,7499],{},"(2) 平均计算",[30,7501,7502,7733],{},[33,7503,7504,1656,7507,701],{},[563,7505,7506],{},"平均周转时间：",[568,7508,7510,7571],{"className":7509},[571],[568,7511,7513],{"className":7512},[575],[577,7514,7515],{"xmlns":579},[581,7516,7517,7568],{},[584,7518,7519,7521,7523,7525,7527,7529,7531,7533,7535,7537,7539,7541,7543,7545,7547,7549,7551,7554,7556,7558,7560],{},[591,7520,1062],{"stretchy":1061},[595,7522,7379],{},[591,7524,1508],{},[595,7526,7402],{},[591,7528,1508],{},[595,7530,293],{},[591,7532,1508],{},[595,7534,255],{},[591,7536,1508],{},[595,7538,7470],{},[591,7540,1508],{},[595,7542,330],{},[591,7544,1071],{"stretchy":1061},[587,7546,607],{"mathvariant":606},[595,7548,343],{},[591,7550,593],{},[595,7552,7553],{},"315",[587,7555,607],{"mathvariant":606},[595,7557,343],{},[591,7559,593],{},[584,7561,7562,7565],{},[595,7563,7564],{"mathvariant":2397},"52.5",[5627,7566,7567],{}," 分钟",[620,7569,7570],{"encoding":622},"(125 + 85 + 20 + 50 + 25 + 10) \u002F 6 = 315 \u002F 6 = \\mathbf{52.5 \\text{ 分钟}}",[568,7572,7574,7595,7613,7631,7649,7667,7692,7711],{"className":7573,"ariaHidden":628},[627],[568,7575,7577,7580,7583,7586,7589,7592],{"className":7576},[632],[568,7578],{"className":7579,"style":662},[636],[568,7581,1062],{"className":7582},[872],[568,7584,7379],{"className":7585},[641],[568,7587],{"className":7588,"style":1256},[647],[568,7590,1508],{"className":7591},[1260],[568,7593],{"className":7594,"style":1256},[647],[568,7596,7598,7601,7604,7607,7610],{"className":7597},[632],[568,7599],{"className":7600,"style":1249},[636],[568,7602,7402],{"className":7603},[641],[568,7605],{"className":7606,"style":1256},[647],[568,7608,1508],{"className":7609},[1260],[568,7611],{"className":7612,"style":1256},[647],[568,7614,7616,7619,7622,7625,7628],{"className":7615},[632],[568,7617],{"className":7618,"style":1249},[636],[568,7620,293],{"className":7621},[641],[568,7623],{"className":7624,"style":1256},[647],[568,7626,1508],{"className":7627},[1260],[568,7629],{"className":7630,"style":1256},[647],[568,7632,7634,7637,7640,7643,7646],{"className":7633},[632],[568,7635],{"className":7636,"style":1249},[636],[568,7638,255],{"className":7639},[641],[568,7641],{"className":7642,"style":1256},[647],[568,7644,1508],{"className":7645},[1260],[568,7647],{"className":7648,"style":1256},[647],[568,7650,7652,7655,7658,7661,7664],{"className":7651},[632],[568,7653],{"className":7654,"style":1249},[636],[568,7656,7470],{"className":7657},[641],[568,7659],{"className":7660,"style":1256},[647],[568,7662,1508],{"className":7663},[1260],[568,7665],{"className":7666,"style":1256},[647],[568,7668,7670,7673,7676,7679,7683,7686,7689],{"className":7669},[632],[568,7671],{"className":7672,"style":662},[636],[568,7674,330],{"className":7675},[641],[568,7677,1071],{"className":7678},[955],[568,7680,7682],{"className":7681},[641],"\u002F6",[568,7684],{"className":7685,"style":648},[647],[568,7687,593],{"className":7688},[652],[568,7690],{"className":7691,"style":648},[647],[568,7693,7695,7698,7702,7705,7708],{"className":7694},[632],[568,7696],{"className":7697,"style":662},[636],[568,7699,7701],{"className":7700},[641],"315\u002F6",[568,7703],{"className":7704,"style":648},[647],[568,7706,593],{"className":7707},[652],[568,7709],{"className":7710,"style":648},[647],[568,7712,7714,7717],{"className":7713},[632],[568,7715],{"className":7716,"style":637},[636],[568,7718,7720,7723],{"className":7719},[641],[568,7721,7564],{"className":7722},[641,2676],[568,7724,7726,7729],{"className":7725},[641,6168],[568,7727,6415],{"className":7728},[641],[568,7730,7732],{"className":7731},[641,6419],"分钟",[33,7734,7735,1656,7738,701],{},[563,7736,7737],{},"平均带权周转时间：",[568,7739,7741,7792],{"className":7740},[571],[568,7742,7744],{"className":7743},[575],[577,7745,7746],{"xmlns":579},[581,7747,7748,7789],{},[584,7749,7750,7752,7755,7757,7760,7762,7765,7767,7769,7771,7773,7775,7778,7780,7782,7784,7786],{},[591,7751,1062],{"stretchy":1061},[595,7753,7754],{},"3.125",[591,7756,1508],{},[595,7758,7759],{},"2.833",[591,7761,1508],{},[595,7763,7764],{},"1.0",[591,7766,1508],{},[595,7768,977],{},[591,7770,1508],{},[595,7772,977],{},[591,7774,1508],{},[595,7776,7777],{},"2.0",[591,7779,1071],{"stretchy":1061},[587,7781,607],{"mathvariant":606},[595,7783,343],{},[591,7785,738],{},[595,7787,7788],{"mathvariant":2397},"2.326",[620,7790,7791],{"encoding":622},"(3.125 + 2.833 + 1.0 + 2.5 + 2.5 + 2.0) \u002F 6 \\approx \\mathbf{2.326}",[568,7793,7795,7816,7834,7852,7870,7888,7912],{"className":7794,"ariaHidden":628},[627],[568,7796,7798,7801,7804,7807,7810,7813],{"className":7797},[632],[568,7799],{"className":7800,"style":662},[636],[568,7802,1062],{"className":7803},[872],[568,7805,7754],{"className":7806},[641],[568,7808],{"className":7809,"style":1256},[647],[568,7811,1508],{"className":7812},[1260],[568,7814],{"className":7815,"style":1256},[647],[568,7817,7819,7822,7825,7828,7831],{"className":7818},[632],[568,7820],{"className":7821,"style":1249},[636],[568,7823,7759],{"className":7824},[641],[568,7826],{"className":7827,"style":1256},[647],[568,7829,1508],{"className":7830},[1260],[568,7832],{"className":7833,"style":1256},[647],[568,7835,7837,7840,7843,7846,7849],{"className":7836},[632],[568,7838],{"className":7839,"style":1249},[636],[568,7841,7764],{"className":7842},[641],[568,7844],{"className":7845,"style":1256},[647],[568,7847,1508],{"className":7848},[1260],[568,7850],{"className":7851,"style":1256},[647],[568,7853,7855,7858,7861,7864,7867],{"className":7854},[632],[568,7856],{"className":7857,"style":1249},[636],[568,7859,977],{"className":7860},[641],[568,7862],{"className":7863,"style":1256},[647],[568,7865,1508],{"className":7866},[1260],[568,7868],{"className":7869,"style":1256},[647],[568,7871,7873,7876,7879,7882,7885],{"className":7872},[632],[568,7874],{"className":7875,"style":1249},[636],[568,7877,977],{"className":7878},[641],[568,7880],{"className":7881,"style":1256},[647],[568,7883,1508],{"className":7884},[1260],[568,7886],{"className":7887,"style":1256},[647],[568,7889,7891,7894,7897,7900,7903,7906,7909],{"className":7890},[632],[568,7892],{"className":7893,"style":662},[636],[568,7895,7777],{"className":7896},[641],[568,7898,1071],{"className":7899},[955],[568,7901,7682],{"className":7902},[641],[568,7904],{"className":7905,"style":648},[647],[568,7907,738],{"className":7908},[652],[568,7910],{"className":7911,"style":648},[647],[568,7913,7915,7918],{"className":7914},[632],[568,7916],{"className":7917,"style":691},[636],[568,7919,7921],{"className":7920},[641],[568,7922,7788],{"className":7923},[641,2676],[26,7925,7926,7928,7929,7932],{},[563,7927,2682],{}," 完全忽视\"四道\"的限制，把5和6早早放进内存引发错误的抢占。记住，",[563,7930,7931],{},"多道度满了之后，大门焊死","，新作业只能在外边排队等。\n:::",[13,7934,7936],{"id":7935},"_20-unix-多级索引节点inode最大文件长度","20. UNIX 多级索引节点（Inode）最大文件长度",[26,7938,7939],{},"设文件索引节点中有 7 个地址项，其中 4 个为直接地址索引，2 个是一级间接地址索引，1 个是二级间接地址索引，地址项大小为 4B，若磁盘索引块和磁盘数据块大小均为 1KB，求可表示的单个文件的最大长度。",[26,7941,41],{},[554,7943,3076],{"id":7944},"答案与详细解答-4",[30,7946,7947,8029,8035,8070,8134,8238],{},[33,7948,7949,1656,7952,8028],{},[563,7950,7951],{},"每个索引块能容纳的指针数：",[568,7953,7955,7985],{"className":7954},[571],[568,7956,7958],{"className":7957},[575],[577,7959,7960],{"xmlns":579},[581,7961,7962,7982],{},[584,7963,7964,7966,7969,7971,7973,7975,7977,7979],{},[595,7965,249],{},[587,7967,7968],{},"K",[587,7970,4671],{},[587,7972,607],{"mathvariant":606},[595,7974,306],{},[587,7976,4671],{},[591,7978,593],{},[595,7980,7981],{},"256",[620,7983,7984],{"encoding":622},"1KB \u002F 4B = 256",[568,7986,7988,8019],{"className":7987,"ariaHidden":628},[627],[568,7989,7991,7994,7997,8000,8003,8007,8010,8013,8016],{"className":7990},[632],[568,7992],{"className":7993,"style":662},[636],[568,7995,249],{"className":7996},[641],[568,7998,7968],{"className":7999,"style":5158},[641,642],[568,8001,4671],{"className":8002,"style":4706},[641,642],[568,8004,8006],{"className":8005},[641],"\u002F4",[568,8008,4671],{"className":8009,"style":4706},[641,642],[568,8011],{"className":8012,"style":648},[647],[568,8014,593],{"className":8015},[652],[568,8017],{"className":8018,"style":648},[647],[568,8020,8022,8025],{"className":8021},[632],[568,8023],{"className":8024,"style":691},[636],[568,8026,7981],{"className":8027},[641]," 个指针。",[33,8030,8031,8034],{},[563,8032,8033],{},"直接寻址："," 4 个指针，指向 4 个物理块。",[33,8036,8037,8040,8041,8069],{},[563,8038,8039],{},"一级间接："," 2 个指针 ",[568,8042,8044,8057],{"className":8043},[571],[568,8045,8047],{"className":8046},[575],[577,8048,8049],{"xmlns":579},[581,8050,8051,8055],{},[584,8052,8053],{},[591,8054,1221],{},[620,8056,6654],{"encoding":622},[568,8058,8060],{"className":8059,"ariaHidden":628},[627],[568,8061,8063,8066],{"className":8062},[632],[568,8064],{"className":8065,"style":6495},[636],[568,8067,1221],{"className":8068},[641]," 256 = 512 个物理块。",[33,8071,8072,8075,8076,8104,8105,8133],{},[563,8073,8074],{},"二级间接："," 1 个指针 ",[568,8077,8079,8092],{"className":8078},[571],[568,8080,8082],{"className":8081},[575],[577,8083,8084],{"xmlns":579},[581,8085,8086,8090],{},[584,8087,8088],{},[591,8089,1221],{},[620,8091,6654],{"encoding":622},[568,8093,8095],{"className":8094,"ariaHidden":628},[627],[568,8096,8098,8101],{"className":8097},[632],[568,8099],{"className":8100,"style":6495},[636],[568,8102,1221],{"className":8103},[641]," 256 ",[568,8106,8108,8121],{"className":8107},[571],[568,8109,8111],{"className":8110},[575],[577,8112,8113],{"xmlns":579},[581,8114,8115,8119],{},[584,8116,8117],{},[591,8118,1221],{},[620,8120,6654],{"encoding":622},[568,8122,8124],{"className":8123,"ariaHidden":628},[627],[568,8125,8127,8130],{"className":8126},[632],[568,8128],{"className":8129,"style":6495},[636],[568,8131,1221],{"className":8132},[641]," 256 = 65536 个物理块。",[33,8135,8136,1656,8139,8237],{},[563,8137,8138],{},"文件最大块数：",[568,8140,8142,8171],{"className":8141},[571],[568,8143,8145],{"className":8144},[575],[577,8146,8147],{"xmlns":579},[581,8148,8149,8168],{},[584,8150,8151,8153,8155,8158,8160,8163,8165],{},[595,8152,306],{},[591,8154,1508],{},[595,8156,8157],{},"512",[591,8159,1508],{},[595,8161,8162],{},"65536",[591,8164,593],{},[595,8166,8167],{},"66052",[620,8169,8170],{"encoding":622},"4 + 512 + 65536 = 66052",[568,8172,8174,8192,8210,8228],{"className":8173,"ariaHidden":628},[627],[568,8175,8177,8180,8183,8186,8189],{"className":8176},[632],[568,8178],{"className":8179,"style":1249},[636],[568,8181,306],{"className":8182},[641],[568,8184],{"className":8185,"style":1256},[647],[568,8187,1508],{"className":8188},[1260],[568,8190],{"className":8191,"style":1256},[647],[568,8193,8195,8198,8201,8204,8207],{"className":8194},[632],[568,8196],{"className":8197,"style":1249},[636],[568,8199,8157],{"className":8200},[641],[568,8202],{"className":8203,"style":1256},[647],[568,8205,1508],{"className":8206},[1260],[568,8208],{"className":8209,"style":1256},[647],[568,8211,8213,8216,8219,8222,8225],{"className":8212},[632],[568,8214],{"className":8215,"style":691},[636],[568,8217,8162],{"className":8218},[641],[568,8220],{"className":8221,"style":648},[647],[568,8223,593],{"className":8224},[652],[568,8226],{"className":8227,"style":648},[647],[568,8229,8231,8234],{"className":8230},[632],[568,8232],{"className":8233,"style":691},[636],[568,8235,8167],{"className":8236},[641]," 块。",[33,8239,8240,8243,8244,8272,8273,8276,8277,8280],{},[563,8241,8242],{},"文件最大长度："," 66052 块 ",[568,8245,8247,8260],{"className":8246},[571],[568,8248,8250],{"className":8249},[575],[577,8251,8252],{"xmlns":579},[581,8253,8254,8258],{},[584,8255,8256],{},[591,8257,1221],{},[620,8259,6654],{"encoding":622},[568,8261,8263],{"className":8262,"ariaHidden":628},[627],[568,8264,8266,8269],{"className":8265},[632],[568,8267],{"className":8268,"style":6495},[636],[568,8270,1221],{"className":8271},[641]," 1KB = ",[563,8274,8275],{},"66052 KB","（即 ",[563,8278,8279],{},"64MB + 516KB","）。\n:::",[13,8282,8284],{"id":8283},"_21-单道调度fcfs-sjf-hrrn-对比","21. 单道调度：FCFS \u002F SJF \u002F HRRN 对比",[26,8286,8287],{},"如果在一段时间内先后有 5 个作业，它们提交和运行时间由下表给出。",[53,8289,8290,8308],{},[56,8291,8292],{},[59,8293,8294,8296,8298,8300,8302,8304,8306],{},[62,8295,224],{"align":64},[62,8297,227],{"align":64},[62,8299,230],{"align":64},[62,8301,233],{"align":64},[62,8303,236],{"align":64},[62,8305,239],{"align":64},[62,8307,242],{"align":64},[73,8309,8310,8326,8342,8358,8374],{},[59,8311,8312,8314,8316,8318,8320,8322,8324],{},[78,8313,249],{"align":64},[78,8315,252],{"align":64},[78,8317,255],{"align":64},[78,8319],{"align":64},[78,8321],{"align":64},[78,8323],{"align":64},[78,8325],{"align":64},[59,8327,8328,8330,8332,8334,8336,8338,8340],{},[78,8329,268],{"align":64},[78,8331,271],{"align":64},[78,8333,274],{"align":64},[78,8335],{"align":64},[78,8337],{"align":64},[78,8339],{"align":64},[78,8341],{"align":64},[59,8343,8344,8346,8348,8350,8352,8354,8356],{},[78,8345,287],{"align":64},[78,8347,290],{"align":64},[78,8349,293],{"align":64},[78,8351],{"align":64},[78,8353],{"align":64},[78,8355],{"align":64},[78,8357],{"align":64},[59,8359,8360,8362,8364,8366,8368,8370,8372],{},[78,8361,306],{"align":64},[78,8363,309],{"align":64},[78,8365,293],{"align":64},[78,8367],{"align":64},[78,8369],{"align":64},[78,8371],{"align":64},[78,8373],{"align":64},[59,8375,8376,8378,8380,8382,8384,8386,8388],{},[78,8377,324],{"align":64},[78,8379,327],{"align":64},[78,8381,330],{"align":64},[78,8383],{"align":64},[78,8385],{"align":64},[78,8387],{"align":64},[78,8389],{"align":64},[26,8391,359],{},[30,8393,8394,8397],{},[33,8395,8396],{},"(1) 分别使用先来先服务、最短进程优先和最高响应比算法完成上表，给出各个作业的开始时间、完成时间、周转时间和带权周转时间；",[33,8398,8399],{},"(2) 计算各算法的平均作业周转时间和平均作业带权周转时间。",[26,8401,41],{},[554,8403,823],{"id":8404},"原理解析-the-why-4",[26,8406,8407,8408,8605],{},"响应比 ",[568,8409,8411,8444],{"className":8410},[571],[568,8412,8414],{"className":8413},[575],[577,8415,8416],{"xmlns":579},[581,8417,8418,8441],{},[584,8419,8420,8427,8429,8431,8433],{},[4138,8421,8422,8425],{},[587,8423,8424],{},"R",[587,8426,8424],{},[591,8428,593],{},[595,8430,249],{},[591,8432,1508],{},[843,8434,8435,8438],{},[5627,8436,8437],{},"等待时间",[5627,8439,8440],{},"服务时间",[620,8442,8443],{"encoding":622},"R_R = 1 + \\frac{\\text{等待时间}}{\\text{服务时间}}",[568,8445,8447,8505,8523],{"className":8446,"ariaHidden":628},[627],[568,8448,8450,8453,8496,8499,8502],{"className":8449},[632],[568,8451],{"className":8452,"style":4187},[636],[568,8454,8456,8460],{"className":8455},[641],[568,8457,8424],{"className":8458,"style":8459},[641,642],"margin-right:0.0077em;",[568,8461,8463],{"className":8462},[4197],[568,8464,8466,8488],{"className":8465},[880,881],[568,8467,8469,8485],{"className":8468},[885],[568,8470,8473],{"className":8471,"style":8472},[889],"height:0.3283em;",[568,8474,8476,8479],{"style":8475},"top:-2.55em;margin-left:-0.0077em;margin-right:0.05em;",[568,8477],{"className":8478,"style":4214},[897],[568,8480,8482],{"className":8481},[902,903,904,905],[568,8483,8424],{"className":8484,"style":8459},[641,642,905],[568,8486,942],{"className":8487},[941],[568,8489,8491],{"className":8490},[885],[568,8492,8494],{"className":8493,"style":4245},[889],[568,8495],{},[568,8497],{"className":8498,"style":648},[647],[568,8500,593],{"className":8501},[652],[568,8503],{"className":8504,"style":648},[647],[568,8506,8508,8511,8514,8517,8520],{"className":8507},[632],[568,8509],{"className":8510,"style":1249},[636],[568,8512,249],{"className":8513},[641],[568,8515],{"className":8516,"style":1256},[647],[568,8518,1508],{"className":8519},[1260],[568,8521],{"className":8522,"style":1256},[647],[568,8524,8526,8530],{"className":8525},[632],[568,8527],{"className":8528,"style":8529},[636],"height:1.2173em;vertical-align:-0.345em;",[568,8531,8533,8536,8602],{"className":8532},[641],[568,8534],{"className":8535},[872,873],[568,8537,8539],{"className":8538},[843],[568,8540,8542,8594],{"className":8541},[880,881],[568,8543,8545,8591],{"className":8544},[885],[568,8546,8549,8566,8574],{"className":8547,"style":8548},[889],"height:0.8723em;",[568,8550,8551,8554],{"style":893},[568,8552],{"className":8553,"style":898},[897],[568,8555,8557],{"className":8556},[902,903,904,905],[568,8558,8560],{"className":8559},[641,905],[568,8561,8563],{"className":8562},[641,6168,905],[568,8564,8440],{"className":8565},[641,6419,905],[568,8567,8568,8571],{"style":914},[568,8569],{"className":8570,"style":898},[897],[568,8572],{"className":8573,"style":922},[921],[568,8575,8576,8579],{"style":925},[568,8577],{"className":8578,"style":898},[897],[568,8580,8582],{"className":8581},[902,903,904,905],[568,8583,8585],{"className":8584},[641,905],[568,8586,8588],{"className":8587},[641,6168,905],[568,8589,8437],{"className":8590},[641,6419,905],[568,8592,942],{"className":8593},[941],[568,8595,8597],{"className":8596},[885],[568,8598,8600],{"className":8599,"style":949},[889],[568,8601],{},[568,8603],{"className":8604},[955,873],"。HRRN在每次有作业完成时，动态计算队列中所有人的响应比，挑最大的执行。",[554,8607,3076],{"id":8608},"答案与详细解答-5",[26,8610,8611],{},[563,8612,8613],{},"(1) FCFS (先来先服务)",[53,8615,8616,8637],{},[56,8617,8618],{},[59,8619,8620,8622,8625,8628,8630,8632,8634],{},[62,8621,7340],{"align":64},[62,8623,8624],{"align":64},"提交",[62,8626,8627],{"align":64},"运行",[62,8629,233],{"align":64},[62,8631,7353],{"align":64},[62,8633,239],{"align":64},[62,8635,8636],{"align":64},"带权周转",[73,8638,8639,8658,8679,8698,8719,8739],{},[59,8640,8641,8645,8647,8649,8651,8654,8656],{},[78,8642,8643],{"align":64},[563,8644,249],{},[78,8646,252],{"align":64},[78,8648,255],{"align":64},[78,8650,252],{"align":64},[78,8652,8653],{"align":64},"8:50",[78,8655,255],{"align":64},[78,8657,7764],{"align":64},[59,8659,8660,8664,8666,8668,8670,8673,8676],{},[78,8661,8662],{"align":64},[563,8663,268],{},[78,8665,271],{"align":64},[78,8667,274],{"align":64},[78,8669,8653],{"align":64},[78,8671,8672],{"align":64},"9:20",[78,8674,8675],{"align":64},"65",[78,8677,8678],{"align":64},"2.167",[59,8680,8681,8685,8687,8689,8691,8693,8695],{},[78,8682,8683],{"align":64},[563,8684,287],{},[78,8686,290],{"align":64},[78,8688,293],{"align":64},[78,8690,8672],{"align":64},[78,8692,7399],{"align":64},[78,8694,1232],{"align":64},[78,8696,8697],{"align":64},"4.0",[59,8699,8700,8704,8706,8708,8710,8713,8716],{},[78,8701,8702],{"align":64},[563,8703,306],{},[78,8705,309],{"align":64},[78,8707,293],{"align":64},[78,8709,7399],{"align":64},[78,8711,8712],{"align":64},"10:00",[78,8714,8715],{"align":64},"95",[78,8717,8718],{"align":64},"4.75",[59,8720,8721,8725,8727,8729,8731,8734,8736],{},[78,8722,8723],{"align":64},[563,8724,324],{},[78,8726,327],{"align":64},[78,8728,330],{"align":64},[78,8730,8712],{"align":64},[78,8732,8733],{"align":64},"10:10",[78,8735,610],{"align":64},[78,8737,8738],{"align":64},"10.0",[59,8740,8741,8849,8851,8853,8855,8857,8859],{},[78,8742,8743,1656,8746,8812,8813,1656,8816],{"align":64},[1662,8744,8745],{},"平均周转:",[568,8747,8749,8777],{"className":8748},[571],[568,8750,8752],{"className":8751},[575],[577,8753,8754],{"xmlns":579},[581,8755,8756,8774],{},[584,8757,8758,8761,8763,8765,8767],{},[595,8759,8760],{},"390",[587,8762,607],{"mathvariant":606},[595,8764,324],{},[591,8766,593],{},[584,8768,8769,8772],{},[595,8770,8771],{"mathvariant":2397},"78",[587,8773,600],{"mathvariant":2397},[620,8775,8776],{"encoding":622},"390 \u002F 5 = \\mathbf{78 m}",[568,8778,8780,8799],{"className":8779,"ariaHidden":628},[627],[568,8781,8783,8786,8790,8793,8796],{"className":8782},[632],[568,8784],{"className":8785,"style":662},[636],[568,8787,8789],{"className":8788},[641],"390\u002F5",[568,8791],{"className":8792,"style":648},[647],[568,8794,593],{"className":8795},[652],[568,8797],{"className":8798,"style":648},[647],[568,8800,8802,8805],{"className":8801},[632],[568,8803],{"className":8804,"style":691},[636],[568,8806,8808],{"className":8807},[641],[568,8809,8811],{"className":8810},[641,2676],"78m","；",[1662,8814,8815],{},"平均带权:",[568,8817,8819,8834],{"className":8818},[571],[568,8820,8822],{"className":8821},[575],[577,8823,8824],{"xmlns":579},[581,8825,8826,8831],{},[584,8827,8828],{},[595,8829,8830],{"mathvariant":2397},"4.383",[620,8832,8833],{"encoding":622},"\\mathbf{4.383}",[568,8835,8837],{"className":8836,"ariaHidden":628},[627],[568,8838,8840,8843],{"className":8839},[632],[568,8841],{"className":8842,"style":691},[636],[568,8844,8846],{"className":8845},[641],[568,8847,8830],{"className":8848},[641,2676],[78,8850],{"align":64},[78,8852],{"align":64},[78,8854],{"align":64},[78,8856],{"align":64},[78,8858],{"align":64},[78,8860],{"align":64},[26,8862,8863],{},[563,8864,8865],{},"(2) SJF (最短作业优先 - 非抢占)",[26,8867,8868,8869,8897,8898,8926,8927,8955,8956,8984],{},"J1(8:00~8:50)。8:50时队列中全员到齐，按运行时间从短到长选：J5(10) > J3(20) = J4(20) > J2(30)。J3比J4早到，故J3先。执行顺序：J1 ",[568,8870,8872,8885],{"className":8871},[571],[568,8873,8875],{"className":8874},[575],[577,8876,8877],{"xmlns":579},[581,8878,8879,8883],{},[584,8880,8881],{},[591,8882,2778],{},[620,8884,2781],{"encoding":622},[568,8886,8888],{"className":8887,"ariaHidden":628},[627],[568,8889,8891,8894],{"className":8890},[632],[568,8892],{"className":8893,"style":2746},[636],[568,8895,2778],{"className":8896},[652]," J5 ",[568,8899,8901,8914],{"className":8900},[571],[568,8902,8904],{"className":8903},[575],[577,8905,8906],{"xmlns":579},[581,8907,8908,8912],{},[584,8909,8910],{},[591,8911,2778],{},[620,8913,2781],{"encoding":622},[568,8915,8917],{"className":8916,"ariaHidden":628},[627],[568,8918,8920,8923],{"className":8919},[632],[568,8921],{"className":8922,"style":2746},[636],[568,8924,2778],{"className":8925},[652]," J3 ",[568,8928,8930,8943],{"className":8929},[571],[568,8931,8933],{"className":8932},[575],[577,8934,8935],{"xmlns":579},[581,8936,8937,8941],{},[584,8938,8939],{},[591,8940,2778],{},[620,8942,2781],{"encoding":622},[568,8944,8946],{"className":8945,"ariaHidden":628},[627],[568,8947,8949,8952],{"className":8948},[632],[568,8950],{"className":8951,"style":2746},[636],[568,8953,2778],{"className":8954},[652]," J4 ",[568,8957,8959,8972],{"className":8958},[571],[568,8960,8962],{"className":8961},[575],[577,8963,8964],{"xmlns":579},[581,8965,8966,8970],{},[584,8967,8968],{},[591,8969,2778],{},[620,8971,2781],{"encoding":622},[568,8973,8975],{"className":8974,"ariaHidden":628},[627],[568,8976,8978,8981],{"className":8977},[632],[568,8979],{"className":8980,"style":2746},[636],[568,8982,2778],{"className":8983},[652]," J2。",[53,8986,8987,9005],{},[56,8988,8989],{},[59,8990,8991,8993,8995,8997,8999,9001,9003],{},[62,8992,7340],{"align":64},[62,8994,8624],{"align":64},[62,8996,8627],{"align":64},[62,8998,233],{"align":64},[62,9000,7353],{"align":64},[62,9002,239],{"align":64},[62,9004,8636],{"align":64},[73,9006,9007,9025,9045,9063,9082,9102],{},[59,9008,9009,9013,9015,9017,9019,9021,9023],{},[78,9010,9011],{"align":64},[563,9012,249],{},[78,9014,252],{"align":64},[78,9016,255],{"align":64},[78,9018,252],{"align":64},[78,9020,8653],{"align":64},[78,9022,255],{"align":64},[78,9024,7764],{"align":64},[59,9026,9027,9031,9033,9035,9037,9040,9042],{},[78,9028,9029],{"align":64},[563,9030,324],{},[78,9032,327],{"align":64},[78,9034,330],{"align":64},[78,9036,8653],{"align":64},[78,9038,9039],{"align":64},"9:00",[78,9041,274],{"align":64},[78,9043,9044],{"align":64},"3.0",[59,9046,9047,9051,9053,9055,9057,9059,9061],{},[78,9048,9049],{"align":64},[563,9050,287],{},[78,9052,290],{"align":64},[78,9054,293],{"align":64},[78,9056,9039],{"align":64},[78,9058,8672],{"align":64},[78,9060,3352],{"align":64},[78,9062,9044],{"align":64},[59,9064,9065,9069,9071,9073,9075,9077,9079],{},[78,9066,9067],{"align":64},[563,9068,306],{},[78,9070,309],{"align":64},[78,9072,293],{"align":64},[78,9074,8672],{"align":64},[78,9076,7399],{"align":64},[78,9078,3701],{"align":64},[78,9080,9081],{"align":64},"3.75",[59,9083,9084,9088,9090,9092,9094,9096,9099],{},[78,9085,9086],{"align":64},[563,9087,268],{},[78,9089,271],{"align":64},[78,9091,274],{"align":64},[78,9093,7399],{"align":64},[78,9095,8733],{"align":64},[78,9097,9098],{"align":64},"115",[78,9100,9101],{"align":64},"3.833",[59,9103,9104,9209,9211,9213,9215,9217,9219],{},[78,9105,9106,1656,9108,8812,9174,1656,9176],{"align":64},[1662,9107,8745],{},[568,9109,9111,9139],{"className":9110},[571],[568,9112,9114],{"className":9113},[575],[577,9115,9116],{"xmlns":579},[581,9117,9118,9136],{},[584,9119,9120,9123,9125,9127,9129],{},[595,9121,9122],{},"330",[587,9124,607],{"mathvariant":606},[595,9126,324],{},[591,9128,593],{},[584,9130,9131,9134],{},[595,9132,9133],{"mathvariant":2397},"66",[587,9135,600],{"mathvariant":2397},[620,9137,9138],{"encoding":622},"330 \u002F 5 = \\mathbf{66 m}",[568,9140,9142,9161],{"className":9141,"ariaHidden":628},[627],[568,9143,9145,9148,9152,9155,9158],{"className":9144},[632],[568,9146],{"className":9147,"style":662},[636],[568,9149,9151],{"className":9150},[641],"330\u002F5",[568,9153],{"className":9154,"style":648},[647],[568,9156,593],{"className":9157},[652],[568,9159],{"className":9160,"style":648},[647],[568,9162,9164,9167],{"className":9163},[632],[568,9165],{"className":9166,"style":691},[636],[568,9168,9170],{"className":9169},[641],[568,9171,9173],{"className":9172},[641,2676],"66m",[1662,9175,8815],{},[568,9177,9179,9194],{"className":9178},[571],[568,9180,9182],{"className":9181},[575],[577,9183,9184],{"xmlns":579},[581,9185,9186,9191],{},[584,9187,9188],{},[595,9189,9190],{"mathvariant":2397},"2.917",[620,9192,9193],{"encoding":622},"\\mathbf{2.917}",[568,9195,9197],{"className":9196,"ariaHidden":628},[627],[568,9198,9200,9203],{"className":9199},[632],[568,9201],{"className":9202,"style":691},[636],[568,9204,9206],{"className":9205},[641],[568,9207,9190],{"className":9208},[641,2676],[78,9210],{"align":64},[78,9212],{"align":64},[78,9214],{"align":64},[78,9216],{"align":64},[78,9218],{"align":64},[78,9220],{"align":64},[26,9222,9223],{},[563,9224,9225],{},"(3) HRRN (最高响应比优先)",[26,9227,9228],{},"对于这组数据，HRRN 的调度顺序与 SJF 完全一致（依然是 1-5-3-4-2），时间表和平均时间同 SJF 算法。\n:::",[13,9230,9232],{"id":9231},"_22-请求分页4页框页面走向-3456356375","22. 请求分页：4页框，页面走向 3,4,5,6,3,5,6,3,7,5",[26,9234,9235],{},"在请求分页管理系统中, 一个程序的页面走向为: 3, 4, 5, 6, 3, 5, 6, 3, 7, 5，设分配给该程序的存储块为 4。所有内存开始时都是空的，凡第一次用到的页面都产生一次缺页中断。",[26,9237,41],{},[26,9239,44],{},[13,9241,9243],{"id":9242},"_23-磁盘顺序文件逻辑记录定位","23. 磁盘顺序文件：逻辑记录定位",[26,9245,9246],{},"假设有一个磁盘组共有 100 个柱面，每个柱面上有 8 个磁道，每个盘面被分成 8 个扇区。现有一个含有 6400 逻辑记录的文件，逻辑记录的大小与扇区一致，该文件以顺序结构的形式被存储到磁盘上。柱面、磁道、扇区的编号从\"0\"开始，逻辑记录的编号也从\"0\"开始。文件信息从 0 柱面、0 磁道、0 扇区开始存放，试问：",[30,9248,9249,9252],{},[33,9250,9251],{},"(1) 该文件的 3680 个逻辑记录应该存放在什么位置？",[33,9253,9254],{},"(2) 78 柱面的 6 磁道的 6 扇区中存放了该文件的第几号逻辑记录？",[26,9256,41],{},[26,9258,44],{},[13,9260,9262],{"id":9261},"_24-生产者-消费者getproput-同步互斥","24. 生产者-消费者：GET\u002FPRO\u002FPUT 同步互斥",[26,9264,9265],{},"如图所示，系统中有三个进程 GET、PRO 和 PUT，共用两个缓冲区 BUF1 和 BUF2。假设 BUF1 中最多可放 11 个信息，现已放入了两个信息；BUF2 最多可放 5 个信息。GET 进程负责不断地将输入信息送入 BUF1 中，PRO 进程负责从 BUF1 中取出信息进行处理，并将处理结果送到 BUF2 中，PUT 进程负责从 BUF2 中读取结果并输出。试写出正确实现 GET、PRO、PUT 的同步与互斥的算法（要求：（1）用类 C 语言描述，条理清楚，注释恰当；（2）信号量原语统一使用 wait 和 signal。）",[9267,9268,9269],"blockquote",{},[26,9270,9271],{},"图 进程合作：GET → BUF1 → PRO → BUF2 → PUT",[26,9273,41],{},[26,9275,44],{},[13,9277,9279],{"id":9278},"_25-死锁判断r1r2-设备申请顺序","25. 死锁判断：R1\u002FR2 设备申请顺序",[26,9281,9282],{},"某系统有 R1 设备 3 台，R2 设备 4 台，它们被 P1、P2、P3 和 P4 进程共享，且已知这 4 个进程均按以下顺序使用设备：",[26,9284,9285],{},[1658,9286,9287],{},"→申请R1→申请R2→申请R1→释放R1→释放R2→释放R1",[30,9289,9290,9293],{},[33,9291,9292],{},"(1) 系统运行中可能产生死锁吗？为什么？",[33,9294,9295],{},"(2) 若可能的话，请举出一种情况，并画出表示该死锁状态的进程—资源图。",[26,9297,41],{},[26,9299,44],{},[13,9301,9303],{"id":9302},"_26-并发进程执行路径与与时间相关的错误","26. 并发进程执行路径与与时间相关的错误",[26,9305,9306],{},"(1) 两个并发进程并发执行，其中，A、B、C、D、E 是原语，试给出可能的并发执行路径。",[9308,9309,9313],"pre",{"className":9310,"code":9312,"language":6168},[9311],"language-text","Process P           Process Q\nbegin               begin\n    A;                  D;\n    B;                  E;\n    C;              end;\nend;\n",[1658,9314,9312],{"__ignoreMap":9315},"",[26,9317,9318],{},"(2) 两个并发进程 P1 和 P2 并发执行，它们的程序分别如下：",[9308,9320,9323],{"className":9321,"code":9322,"language":6168},[9311],"      P1                P2\n    repeat            repeat\n      k:=k×2;         print k;\n      k:=k+1;           k:=0;\n    until false;      until false;\n",[1658,9324,9322],{"__ignoreMap":9315},[26,9326,9327],{},"若令 k 的初值为 5，让 P1 先执行两个循环，然后，P1 和 P2 又并发执行了一个循环，写出可能的打印值，指出与时间有关的错误。",[26,9329,41],{},[26,9331,44],{},[13,9333,9335],{"id":9334},"_27-快表命中率计算","27. 快表命中率计算",[26,9337,9338],{},"一台计算机的内存空间为 1024 个页面，页表放在内存中，从页表中读一个字的开销是 500ns。为了减少开销，使用了有 32 个字的快表，查找速度为 100ns。要把平均开销降到 200ns 需要的快表命中率是多少?",[26,9340,41],{},[26,9342,44],{},[13,9344,9346],{"id":9345},"_28-磁带分块存储与利用率","28. 磁带分块存储与利用率",[26,9348,9349],{},"假定磁带记录密度为每英寸 800 字符，每一逻辑记录为 200 字符，块间隔为 0.6 英寸。现有 3200 个逻辑记录需要存储，如果不考虑存储记录，则不成组处理和以 8 个逻辑记录为一组的成组处理时磁带的利用率各是多少？两种情况下，3200 个逻辑记录需要占用多少磁带空间？",[26,9351,41],{},[26,9353,44],{},[13,9355,9357],{"id":9356},"_29-unix-文件权限判断","29. UNIX 文件权限判断",[26,9359,9360,9361,9364],{},"一个 UNIX 文件 F 的存取权限为：",[1658,9362,9363],{},"rwxr-x---","，该文件的文件主 uid＝12，gid=1，另一个用户的 uid=6，gid=1，是否允许该用户执行文件 F？",[26,9366,41],{},[26,9368,44],{},[13,9370,9372],{"id":9371},"_30-unixlinux-文件访问偏移间接次数","30. UNIX\u002FLinux 文件访问偏移：间接次数",[26,9374,9375],{},"一个 UNIX\u002FLinux 文件，如果一个盘块的大小为 1KB，每个盘块占 4 个字节，那么，若进程欲访问偏移为 263168 字节处的数据，需经过几次间接？",[26,9377,41],{},[26,9379,44],{},[13,9381,9383],{"id":9382},"_31-磁盘交错存储20msr8扇区","31. 磁盘交错存储：20ms\u002Fr、8扇区",[26,9385,9386],{},"假设有 8 个记录 A、B，C、D、E、F、G、H 存放在磁盘里，每个磁道有 8 个扇区，正好可以存放 8 个记录。假设磁盘旋转速度为 20ms\u002F转，处理程序每读出一个记录后，用 2ms 的时间进行处理，请问：",[30,9388,9389,9392],{},[33,9390,9391],{},"a. 当记录 A、B、C、D、E、F、G、H 按顺序放在磁道上时，顺序处理这 8 个记录花费的总时间是多少？假设启动时的位置正好在 A 扇区的起点。",[33,9393,9394],{},"b. 如何采取优化方法，使处理这些记录所花费的总时间最短？求出该最短时间。",[26,9396,41],{},[26,9398,44],{},[13,9400,9402],{"id":9401},"_32-可变分区管理sjf-与-hrrn-调度","32. 可变分区管理：SJF 与 HRRN 调度",[26,9404,9405],{},"系统采用不能移动的可变分区管理方案，现有可供用户使用的主存空间为 100K，设有四个作业 J1, J2, J3, J4 它们的到达时间和计算时间如下表:",[53,9407,9408,9425],{},[56,9409,9410],{},[59,9411,9412,9414,9417,9420,9423],{},[62,9413,7340],{"align":64},[62,9415,9416],{"align":64},"到达时间",[62,9418,9419],{"align":64},"计算时间",[62,9421,9422],{"align":64},"需要主存容量",[62,9424,239],{"align":64},[73,9426,9427,9442,9457,9471],{},[59,9428,9429,9432,9434,9437,9440],{},[78,9430,9431],{"align":64},"J1",[78,9433,252],{"align":64},[78,9435,9436],{"align":64},"40分钟",[78,9438,9439],{"align":64},"30K",[78,9441],{"align":64},[59,9443,9444,9447,9449,9452,9455],{},[78,9445,9446],{"align":64},"J2",[78,9448,290],{"align":64},[78,9450,9451],{"align":64},"35分钟",[78,9453,9454],{"align":64},"70K",[78,9456],{"align":64},[59,9458,9459,9462,9464,9467,9469],{},[78,9460,9461],{"align":64},"J3",[78,9463,327],{"align":64},[78,9465,9466],{"align":64},"20分钟",[78,9468,9439],{"align":64},[78,9470],{"align":64},[59,9472,9473,9476,9478,9481,9484],{},[78,9474,9475],{"align":64},"J4",[78,9477,7422],{"align":64},[78,9479,9480],{"align":64},"10分钟",[78,9482,9483],{"align":64},"20K",[78,9485],{"align":64},[26,9487,9488],{},"若作业在处理机上按单道方式运行，请分别写出：",[30,9490,9491,9494],{},[33,9492,9493],{},"（1）最短者优先算法选中作业的执行顺序，并计算周转时间和平均周转时间。",[33,9495,9496],{},"（2）响应比高者优先算法选中作业的执行顺序，并计算周转时间和平均周转时间。",[26,9498,41],{},[26,9500,44],{},[13,9502,9504],{"id":9503},"_33-分页式虚存fifo-与-lru-缺页中断对比","33. 分页式虚存：FIFO 与 LRU 缺页中断对比",[26,9506,9507],{},"使用\"分页式\"虚拟存储管理技术，假设一个进程 P 的页面访问顺序如下：0 1 2 3 0 1 4 0 1 2 3 4。该进程创建时没有加载任何页面，即该进程启动时其所有指令和数据都不在内存中。",[30,9509,9510,9513,9516],{},[33,9511,9512],{},"(1) 设分配给该进程的物理页帧为 3 个，使用 FIFO 页面置换算法时，请问会发生多少次缺页中断？使用硬件实现的 LRU 算法，会发生多少次缺页中断？",[33,9514,9515],{},"(2) 对于以上两种页面置换算法，如希望减少缺页中断的次数，是否可以通过增加物理页帧来解决？为什么？",[33,9517,9518],{},"(3) 在分页系统中将 I\u002FO 设备的数据缓冲区映射到内存空间后，其对应的页面是否能够被替换？为什么？",[26,9520,41],{},[554,9522,9524],{"id":9523},"概念核对-concept-check","概念核对 (Concept Check)",[30,9526,9527,9533,9539],{},[33,9528,9529,9532],{},[563,9530,9531],{},"FIFO (先进先出)","：淘汰在内存中驻留时间最久的页面。",[33,9534,9535,9538],{},[563,9536,9537],{},"LRU (最近最少使用)","：淘汰最长时间没有被访问过的页面。",[33,9540,9541,9544],{},[563,9542,9543],{},"缺页中断 (Page Fault)","：当 CPU 访问的页面不在实体内存中时触发。",[554,9546,3076],{"id":9547},"答案与详细解答-6",[26,9549,9550],{},[563,9551,9552],{},"(1) 缺页中断次数模拟：",[30,9554,9555,9564],{},[33,9556,9557,9560,9561],{},[563,9558,9559],{},"FIFO 算法 (3个页框)：","\n0(缺) → 1(缺) → 2(缺) → 3(缺，淘汰0) → 0(缺，淘汰1) → 1(缺，淘汰2) → 4(缺，淘汰3) → 0(命中) → 1(命中) → 2(缺，淘汰0) → 3(缺，淘汰1) → 4(命中)\n",[563,9562,9563],{},"总计：发生 9 次缺页中断。",[33,9565,9566,9569,9570],{},[563,9567,9568],{},"LRU 算法 (3个页框)：","\n0(缺) → 1(缺) → 2(缺) → 3(缺，淘汰0) → 0(缺，淘汰1) → 1(缺，淘汰2) → 4(缺，淘汰3) → 0(命中，更新) → 1(命中，更新) → 2(缺，淘汰4) → 3(缺，淘汰0) → 4(缺，淘汰1)\n",[563,9571,9572],{},"总计：发生 10 次缺页中断。",[26,9574,9575],{},[563,9576,9577],{},"(2) 增加物理页框是否能减少缺页？",[30,9579,9580,9586],{},[33,9581,9582,9585],{},[563,9583,9584],{},"LRU：可以。"," 增加页框一定能减少或维持缺页次数（LRU 符合堆栈属性 Stack Property）。",[33,9587,9588,9591,9592,9595],{},[563,9589,9590],{},"FIFO：不一定。"," FIFO 算法可能会遭遇 ",[563,9593,9594],{},"Belady 异常 (Belady's Anomaly)","。对于某些特定的访问序列，增加分配的物理页框数量反而会导致缺页次数上升。",[26,9597,9598],{},[563,9599,9600],{},"(3) 映射到内存的 I\u002FO 缓冲页面能否被替换？",[30,9602,9603,9608],{},[33,9604,9605],{},[563,9606,9607],{},"不能。",[33,9609,9610,9613,9614,9617],{},[563,9611,9612],{},"原因："," 如果正在进行 I\u002FO 操作（如 DMA 传输）的页面被置换到磁盘，而另一个进程的数据刚好载入这个物理页框，那么硬件 I\u002FO 设备会将数据直接覆盖掉无辜进程的内存，造成严重的数据损坏。因此，涉及 I\u002FO 的页面必须被",[563,9615,9616],{},"锁定 (Pinned\u002FLocked)"," 在主存中，禁止被替换。",[26,9619,9620,9623],{},[563,9621,9622],{},"常见易错点："," 学生常会直觉认为\"更好的算法\"在任何情况下都会比\"简单的算法\"表现好。这题恰好反直觉，LRU（10次）的缺页次数反而高于 FIFO（9次）。\n:::",[13,9625,9627],{"id":9626},"_34-连接文件逻辑字节访问对应物理块","34. 连接文件：逻辑字节访问对应物理块",[26,9629,9630],{},"设某文件为连接文件，由 5 个逻辑记录组成，每个逻辑记录的大小与磁盘块大小相等，均为 512 字节，并依次存放在 50、121、75、80、63 号磁盘块上。若要存取文件的第 1569 逻辑字节处的信息，问要访问哪一个磁盘块？",[26,9632,41],{},[554,9634,3076],{"id":9635},"答案与详细解答-7",[26,9637,9638],{},"已知每个逻辑记录和磁盘块的大小为 512 Bytes。",[9640,9641,9642,9760,9780],"ol",{},[33,9643,9644,9645,9751,9752,9755,9756,9759],{},"计算目标字节位于第几个逻辑记录：\n",[568,9646,9648,9680],{"className":9647},[571],[568,9649,9651],{"className":9650},[575],[577,9652,9653],{"xmlns":579},[581,9654,9655,9677],{},[584,9656,9657,9660,9663,9665,9667,9669,9672,9675],{},[595,9658,9659],{},"1569",[591,9661,9662],{},"÷",[595,9664,8157],{},[591,9666,593],{},[595,9668,287],{},[591,9670,9671],{},"…",[5627,9673,9674],{},"余数 ",[595,9676,6210],{},[620,9678,9679],{"encoding":622},"1569 \\div 512 = 3 \\ldots \\text{余数 } 33",[568,9681,9683,9701,9719],{"className":9682,"ariaHidden":628},[627],[568,9684,9686,9689,9692,9695,9698],{"className":9685},[632],[568,9687],{"className":9688,"style":1249},[636],[568,9690,9659],{"className":9691},[641],[568,9693],{"className":9694,"style":1256},[647],[568,9696,9662],{"className":9697},[1260],[568,9699],{"className":9700,"style":1256},[647],[568,9702,9704,9707,9710,9713,9716],{"className":9703},[632],[568,9705],{"className":9706,"style":691},[636],[568,9708,8157],{"className":9709},[641],[568,9711],{"className":9712,"style":648},[647],[568,9714,593],{"className":9715},[652],[568,9717],{"className":9718,"style":648},[647],[568,9720,9722,9725,9728,9731,9735,9738,9748],{"className":9721},[632],[568,9723],{"className":9724,"style":637},[636],[568,9726,287],{"className":9727},[641],[568,9729],{"className":9730,"style":6813},[647],[568,9732,9671],{"className":9733},[9734],"minner",[568,9736],{"className":9737,"style":6813},[647],[568,9739,9741,9745],{"className":9740},[641,6168],[568,9742,9744],{"className":9743},[641,6419],"余数",[568,9746,6415],{"className":9747},[641],[568,9749,6210],{"className":9750},[641],"。\n这表示第 1569 个字节位在",[563,9753,9754],{},"第 3 个完整的逻辑块之后","（也就是进入了",[563,9757,9758],{},"第 4 个逻辑记录","，索引为 3），偏移量为 33。",[33,9761,9762,9763],{},"对应物理磁盘块顺序（从0开始索引）：\n",[30,9764,9765,9768,9771,9774],{},[33,9766,9767],{},"索引 0：第 50 号块",[33,9769,9770],{},"索引 1：第 121 号块",[33,9772,9773],{},"索引 2：第 75 号块",[33,9775,9776,9777],{},"索引 3：",[563,9778,9779],{},"第 80 号块",[33,9781,9782,9783,701],{},"因此，需要访问的是",[563,9784,9785],{},"第 80 号磁盘块",[26,9787,9788,9790],{},[563,9789,9622],{}," 商为 3 代表前面已经有 3 个完整的块（索引0, 1, 2），数据落在下一个块（索引 3），也就是清单中的第 4 个块。\n:::",[13,9792,9794],{"id":9793},"_35-hrrn-调度五个作业响应比与周转时间","35. HRRN 调度：五个作业响应比与周转时间",[26,9796,9797],{},"设有某系统可供用户使用的主存空间为 100K，有五个作业 J1, J2, J3, J4, J5 进入输入井的时间、计算时间和内存要求如下表所示。若作业在处理机上按单道方式运行，且作业按响应比高者优先调度算法，进程按先来先服务算法。试写出作业的执行顺序，计算响应比、作业的周转时间和平均周转时间。",[53,9799,9800,9819],{},[56,9801,9802],{},[59,9803,9804,9806,9809,9811,9813,9815,9817],{},[62,9805,7340],{"align":64},[62,9807,9808],{"align":64},"进入输入井时间",[62,9810,9419],{"align":64},[62,9812,9422],{"align":64},[62,9814,233],{"align":64},[62,9816,236],{"align":64},[62,9818,239],{"align":64},[73,9820,9821,9840,9859,9878,9896],{},[59,9822,9823,9825,9828,9831,9834,9836,9838],{},[78,9824,9431],{"align":64},[78,9826,9827],{"align":64},"10:06",[78,9829,9830],{"align":64},"42分钟",[78,9832,9833],{"align":64},"18K",[78,9835],{"align":64},[78,9837],{"align":64},[78,9839],{"align":64},[59,9841,9842,9844,9847,9850,9853,9855,9857],{},[78,9843,9446],{"align":64},[78,9845,9846],{"align":64},"10:19",[78,9848,9849],{"align":64},"30分钟",[78,9851,9852],{"align":64},"65K",[78,9854],{"align":64},[78,9856],{"align":64},[78,9858],{"align":64},[59,9860,9861,9863,9866,9869,9872,9874,9876],{},[78,9862,9461],{"align":64},[78,9864,9865],{"align":64},"10:30",[78,9867,9868],{"align":64},"24分钟",[78,9870,9871],{"align":64},"57K",[78,9873],{"align":64},[78,9875],{"align":64},[78,9877],{"align":64},[59,9879,9880,9882,9885,9887,9890,9892,9894],{},[78,9881,9475],{"align":64},[78,9883,9884],{"align":64},"10:36",[78,9886,9868],{"align":64},[78,9888,9889],{"align":64},"15K",[78,9891],{"align":64},[78,9893],{"align":64},[78,9895],{"align":64},[59,9897,9898,9901,9904,9907,9910,9912,9914],{},[78,9899,9900],{"align":64},"J5",[78,9902,9903],{"align":64},"10:42",[78,9905,9906],{"align":64},"12分钟",[78,9908,9909],{"align":64},"25K",[78,9911],{"align":64},[78,9913],{"align":64},[78,9915],{"align":64},[26,9917,41],{},[554,9919,3076],{"id":9920},"答案与详细解答-8",[30,9922,9923,9932,10531,10983,11290],{},[33,9924,9925,9927,9928,9931],{},[563,9926,9827],{},"，只有 J1 到达。J1 开始执行。J1 执行 42 分钟，结束时间为 ",[563,9929,9930],{},"10:48","。J1 周转时间 = 42 分。",[33,9933,9934,9936,9937],{},[563,9935,9930],{},"，此时 J2, J3, J4, J5 皆已到达，计算响应比：\n",[30,9938,9939,10086,10233,10378,10521],{},[33,9940,9941,9942],{},"J2 等待 = 29分。",[568,9943,9945,9981],{"className":9944},[571],[568,9946,9948],{"className":9947},[575],[577,9949,9950],{"xmlns":579},[581,9951,9952,9978],{},[584,9953,9954,9960,9962,9964,9966,9969,9971,9973,9975],{},[4138,9955,9956,9958],{},[587,9957,8424],{},[595,9959,268],{},[591,9961,593],{},[595,9963,249],{},[591,9965,1508],{},[595,9967,9968],{},"29",[587,9970,607],{"mathvariant":606},[595,9972,274],{},[591,9974,593],{},[595,9976,9977],{},"1.967",[620,9979,9980],{"encoding":622},"R_2 = 1 + 29\u002F30 = 1.967",[568,9982,9984,10040,10058,10077],{"className":9983,"ariaHidden":628},[627],[568,9985,9987,9990,10031,10034,10037],{"className":9986},[632],[568,9988],{"className":9989,"style":4187},[636],[568,9991,9993,9996],{"className":9992},[641],[568,9994,8424],{"className":9995,"style":8459},[641,642],[568,9997,9999],{"className":9998},[4197],[568,10000,10002,10023],{"className":10001},[880,881],[568,10003,10005,10020],{"className":10004},[885],[568,10006,10009],{"className":10007,"style":10008},[889],"height:0.3011em;",[568,10010,10011,10014],{"style":8475},[568,10012],{"className":10013,"style":4214},[897],[568,10015,10017],{"className":10016},[902,903,904,905],[568,10018,268],{"className":10019},[641,905],[568,10021,942],{"className":10022},[941],[568,10024,10026],{"className":10025},[885],[568,10027,10029],{"className":10028,"style":4245},[889],[568,10030],{},[568,10032],{"className":10033,"style":648},[647],[568,10035,593],{"className":10036},[652],[568,10038],{"className":10039,"style":648},[647],[568,10041,10043,10046,10049,10052,10055],{"className":10042},[632],[568,10044],{"className":10045,"style":1249},[636],[568,10047,249],{"className":10048},[641],[568,10050],{"className":10051,"style":1256},[647],[568,10053,1508],{"className":10054},[1260],[568,10056],{"className":10057,"style":1256},[647],[568,10059,10061,10064,10068,10071,10074],{"className":10060},[632],[568,10062],{"className":10063,"style":662},[636],[568,10065,10067],{"className":10066},[641],"29\u002F30",[568,10069],{"className":10070,"style":648},[647],[568,10072,593],{"className":10073},[652],[568,10075],{"className":10076,"style":648},[647],[568,10078,10080,10083],{"className":10079},[632],[568,10081],{"className":10082,"style":691},[636],[568,10084,9977],{"className":10085},[641],[33,10087,10088,10089],{},"J3 等待 = 18分。",[568,10090,10092,10129],{"className":10091},[571],[568,10093,10095],{"className":10094},[575],[577,10096,10097],{"xmlns":579},[581,10098,10099,10126],{},[584,10100,10101,10107,10109,10111,10113,10116,10118,10121,10123],{},[4138,10102,10103,10105],{},[587,10104,8424],{},[595,10106,287],{},[591,10108,593],{},[595,10110,249],{},[591,10112,1508],{},[595,10114,10115],{},"18",[587,10117,607],{"mathvariant":606},[595,10119,10120],{},"24",[591,10122,593],{},[595,10124,10125],{},"1.75",[620,10127,10128],{"encoding":622},"R_3 = 1 + 18\u002F24 = 1.75",[568,10130,10132,10187,10205,10224],{"className":10131,"ariaHidden":628},[627],[568,10133,10135,10138,10178,10181,10184],{"className":10134},[632],[568,10136],{"className":10137,"style":4187},[636],[568,10139,10141,10144],{"className":10140},[641],[568,10142,8424],{"className":10143,"style":8459},[641,642],[568,10145,10147],{"className":10146},[4197],[568,10148,10150,10170],{"className":10149},[880,881],[568,10151,10153,10167],{"className":10152},[885],[568,10154,10156],{"className":10155,"style":10008},[889],[568,10157,10158,10161],{"style":8475},[568,10159],{"className":10160,"style":4214},[897],[568,10162,10164],{"className":10163},[902,903,904,905],[568,10165,287],{"className":10166},[641,905],[568,10168,942],{"className":10169},[941],[568,10171,10173],{"className":10172},[885],[568,10174,10176],{"className":10175,"style":4245},[889],[568,10177],{},[568,10179],{"className":10180,"style":648},[647],[568,10182,593],{"className":10183},[652],[568,10185],{"className":10186,"style":648},[647],[568,10188,10190,10193,10196,10199,10202],{"className":10189},[632],[568,10191],{"className":10192,"style":1249},[636],[568,10194,249],{"className":10195},[641],[568,10197],{"className":10198,"style":1256},[647],[568,10200,1508],{"className":10201},[1260],[568,10203],{"className":10204,"style":1256},[647],[568,10206,10208,10211,10215,10218,10221],{"className":10207},[632],[568,10209],{"className":10210,"style":662},[636],[568,10212,10214],{"className":10213},[641],"18\u002F24",[568,10216],{"className":10217,"style":648},[647],[568,10219,593],{"className":10220},[652],[568,10222],{"className":10223,"style":648},[647],[568,10225,10227,10230],{"className":10226},[632],[568,10228],{"className":10229,"style":691},[636],[568,10231,10125],{"className":10232},[641],[33,10234,10235,10236],{},"J4 等待 = 12分。",[568,10237,10239,10274],{"className":10238},[571],[568,10240,10242],{"className":10241},[575],[577,10243,10244],{"xmlns":579},[581,10245,10246,10271],{},[584,10247,10248,10254,10256,10258,10260,10262,10264,10266,10268],{},[4138,10249,10250,10252],{},[587,10251,8424],{},[595,10253,306],{},[591,10255,593],{},[595,10257,249],{},[591,10259,1508],{},[595,10261,3694],{},[587,10263,607],{"mathvariant":606},[595,10265,10120],{},[591,10267,593],{},[595,10269,10270],{},"1.5",[620,10272,10273],{"encoding":622},"R_4 = 1 + 12\u002F24 = 1.5",[568,10275,10277,10332,10350,10369],{"className":10276,"ariaHidden":628},[627],[568,10278,10280,10283,10323,10326,10329],{"className":10279},[632],[568,10281],{"className":10282,"style":4187},[636],[568,10284,10286,10289],{"className":10285},[641],[568,10287,8424],{"className":10288,"style":8459},[641,642],[568,10290,10292],{"className":10291},[4197],[568,10293,10295,10315],{"className":10294},[880,881],[568,10296,10298,10312],{"className":10297},[885],[568,10299,10301],{"className":10300,"style":10008},[889],[568,10302,10303,10306],{"style":8475},[568,10304],{"className":10305,"style":4214},[897],[568,10307,10309],{"className":10308},[902,903,904,905],[568,10310,306],{"className":10311},[641,905],[568,10313,942],{"className":10314},[941],[568,10316,10318],{"className":10317},[885],[568,10319,10321],{"className":10320,"style":4245},[889],[568,10322],{},[568,10324],{"className":10325,"style":648},[647],[568,10327,593],{"className":10328},[652],[568,10330],{"className":10331,"style":648},[647],[568,10333,10335,10338,10341,10344,10347],{"className":10334},[632],[568,10336],{"className":10337,"style":1249},[636],[568,10339,249],{"className":10340},[641],[568,10342],{"className":10343,"style":1256},[647],[568,10345,1508],{"className":10346},[1260],[568,10348],{"className":10349,"style":1256},[647],[568,10351,10353,10356,10360,10363,10366],{"className":10352},[632],[568,10354],{"className":10355,"style":662},[636],[568,10357,10359],{"className":10358},[641],"12\u002F24",[568,10361],{"className":10362,"style":648},[647],[568,10364,593],{"className":10365},[652],[568,10367],{"className":10368,"style":648},[647],[568,10370,10372,10375],{"className":10371},[632],[568,10373],{"className":10374,"style":691},[636],[568,10376,10270],{"className":10377},[641],[33,10379,10380,10381],{},"J5 等待 = 6分。",[568,10382,10384,10418],{"className":10383},[571],[568,10385,10387],{"className":10386},[575],[577,10388,10389],{"xmlns":579},[581,10390,10391,10415],{},[584,10392,10393,10399,10401,10403,10405,10407,10409,10411,10413],{},[4138,10394,10395,10397],{},[587,10396,8424],{},[595,10398,324],{},[591,10400,593],{},[595,10402,249],{},[591,10404,1508],{},[595,10406,343],{},[587,10408,607],{"mathvariant":606},[595,10410,3694],{},[591,10412,593],{},[595,10414,10270],{},[620,10416,10417],{"encoding":622},"R_5 = 1 + 6\u002F12 = 1.5",[568,10419,10421,10476,10494,10512],{"className":10420,"ariaHidden":628},[627],[568,10422,10424,10427,10467,10470,10473],{"className":10423},[632],[568,10425],{"className":10426,"style":4187},[636],[568,10428,10430,10433],{"className":10429},[641],[568,10431,8424],{"className":10432,"style":8459},[641,642],[568,10434,10436],{"className":10435},[4197],[568,10437,10439,10459],{"className":10438},[880,881],[568,10440,10442,10456],{"className":10441},[885],[568,10443,10445],{"className":10444,"style":10008},[889],[568,10446,10447,10450],{"style":8475},[568,10448],{"className":10449,"style":4214},[897],[568,10451,10453],{"className":10452},[902,903,904,905],[568,10454,324],{"className":10455},[641,905],[568,10457,942],{"className":10458},[941],[568,10460,10462],{"className":10461},[885],[568,10463,10465],{"className":10464,"style":4245},[889],[568,10466],{},[568,10468],{"className":10469,"style":648},[647],[568,10471,593],{"className":10472},[652],[568,10474],{"className":10475,"style":648},[647],[568,10477,10479,10482,10485,10488,10491],{"className":10478},[632],[568,10480],{"className":10481,"style":1249},[636],[568,10483,249],{"className":10484},[641],[568,10486],{"className":10487,"style":1256},[647],[568,10489,1508],{"className":10490},[1260],[568,10492],{"className":10493,"style":1256},[647],[568,10495,10497,10500,10503,10506,10509],{"className":10496},[632],[568,10498],{"className":10499,"style":662},[636],[568,10501,3837],{"className":10502},[641],[568,10504],{"className":10505,"style":648},[647],[568,10507,593],{"className":10508},[652],[568,10510],{"className":10511,"style":648},[647],[568,10513,10515,10518],{"className":10514},[632],[568,10516],{"className":10517,"style":691},[636],[568,10519,10270],{"className":10520},[641],[33,10522,10523,10524,10526,10527,10530],{},"最高者为 ",[563,10525,9446],{},"。J2 执行 30 分钟，结束时间为 ",[563,10528,10529],{},"11:18","。J2 周转时间 = 59分。",[33,10532,10533,10535,10536],{},[563,10534,10529],{},"，J3, J4, J5 继续竞争：\n",[30,10537,10538,10683,10829,10974],{},[33,10539,10540,10541],{},"J3 等待 = 48分。",[568,10542,10544,10579],{"className":10543},[571],[568,10545,10547],{"className":10546},[575],[577,10548,10549],{"xmlns":579},[581,10550,10551,10576],{},[584,10552,10553,10559,10561,10563,10565,10568,10570,10572,10574],{},[4138,10554,10555,10557],{},[587,10556,8424],{},[595,10558,287],{},[591,10560,593],{},[595,10562,249],{},[591,10564,1508],{},[595,10566,10567],{},"48",[587,10569,607],{"mathvariant":606},[595,10571,10120],{},[591,10573,593],{},[595,10575,9044],{},[620,10577,10578],{"encoding":622},"R_3 = 1 + 48\u002F24 = 3.0",[568,10580,10582,10637,10655,10674],{"className":10581,"ariaHidden":628},[627],[568,10583,10585,10588,10628,10631,10634],{"className":10584},[632],[568,10586],{"className":10587,"style":4187},[636],[568,10589,10591,10594],{"className":10590},[641],[568,10592,8424],{"className":10593,"style":8459},[641,642],[568,10595,10597],{"className":10596},[4197],[568,10598,10600,10620],{"className":10599},[880,881],[568,10601,10603,10617],{"className":10602},[885],[568,10604,10606],{"className":10605,"style":10008},[889],[568,10607,10608,10611],{"style":8475},[568,10609],{"className":10610,"style":4214},[897],[568,10612,10614],{"className":10613},[902,903,904,905],[568,10615,287],{"className":10616},[641,905],[568,10618,942],{"className":10619},[941],[568,10621,10623],{"className":10622},[885],[568,10624,10626],{"className":10625,"style":4245},[889],[568,10627],{},[568,10629],{"className":10630,"style":648},[647],[568,10632,593],{"className":10633},[652],[568,10635],{"className":10636,"style":648},[647],[568,10638,10640,10643,10646,10649,10652],{"className":10639},[632],[568,10641],{"className":10642,"style":1249},[636],[568,10644,249],{"className":10645},[641],[568,10647],{"className":10648,"style":1256},[647],[568,10650,1508],{"className":10651},[1260],[568,10653],{"className":10654,"style":1256},[647],[568,10656,10658,10661,10665,10668,10671],{"className":10657},[632],[568,10659],{"className":10660,"style":662},[636],[568,10662,10664],{"className":10663},[641],"48\u002F24",[568,10666],{"className":10667,"style":648},[647],[568,10669,593],{"className":10670},[652],[568,10672],{"className":10673,"style":648},[647],[568,10675,10677,10680],{"className":10676},[632],[568,10678],{"className":10679,"style":691},[636],[568,10681,9044],{"className":10682},[641],[33,10684,10685,10686],{},"J4 等待 = 42分。",[568,10687,10689,10725],{"className":10688},[571],[568,10690,10692],{"className":10691},[575],[577,10693,10694],{"xmlns":579},[581,10695,10696,10722],{},[584,10697,10698,10704,10706,10708,10710,10713,10715,10717,10719],{},[4138,10699,10700,10702],{},[587,10701,8424],{},[595,10703,306],{},[591,10705,593],{},[595,10707,249],{},[591,10709,1508],{},[595,10711,10712],{},"42",[587,10714,607],{"mathvariant":606},[595,10716,10120],{},[591,10718,593],{},[595,10720,10721],{},"2.75",[620,10723,10724],{"encoding":622},"R_4 = 1 + 42\u002F24 = 2.75",[568,10726,10728,10783,10801,10820],{"className":10727,"ariaHidden":628},[627],[568,10729,10731,10734,10774,10777,10780],{"className":10730},[632],[568,10732],{"className":10733,"style":4187},[636],[568,10735,10737,10740],{"className":10736},[641],[568,10738,8424],{"className":10739,"style":8459},[641,642],[568,10741,10743],{"className":10742},[4197],[568,10744,10746,10766],{"className":10745},[880,881],[568,10747,10749,10763],{"className":10748},[885],[568,10750,10752],{"className":10751,"style":10008},[889],[568,10753,10754,10757],{"style":8475},[568,10755],{"className":10756,"style":4214},[897],[568,10758,10760],{"className":10759},[902,903,904,905],[568,10761,306],{"className":10762},[641,905],[568,10764,942],{"className":10765},[941],[568,10767,10769],{"className":10768},[885],[568,10770,10772],{"className":10771,"style":4245},[889],[568,10773],{},[568,10775],{"className":10776,"style":648},[647],[568,10778,593],{"className":10779},[652],[568,10781],{"className":10782,"style":648},[647],[568,10784,10786,10789,10792,10795,10798],{"className":10785},[632],[568,10787],{"className":10788,"style":1249},[636],[568,10790,249],{"className":10791},[641],[568,10793],{"className":10794,"style":1256},[647],[568,10796,1508],{"className":10797},[1260],[568,10799],{"className":10800,"style":1256},[647],[568,10802,10804,10807,10811,10814,10817],{"className":10803},[632],[568,10805],{"className":10806,"style":662},[636],[568,10808,10810],{"className":10809},[641],"42\u002F24",[568,10812],{"className":10813,"style":648},[647],[568,10815,593],{"className":10816},[652],[568,10818],{"className":10819,"style":648},[647],[568,10821,10823,10826],{"className":10822},[632],[568,10824],{"className":10825,"style":691},[636],[568,10827,10721],{"className":10828},[641],[33,10830,10831,10832],{},"J5 等待 = 36分。",[568,10833,10835,10870],{"className":10834},[571],[568,10836,10838],{"className":10837},[575],[577,10839,10840],{"xmlns":579},[581,10841,10842,10867],{},[584,10843,10844,10850,10852,10854,10856,10859,10861,10863,10865],{},[4138,10845,10846,10848],{},[587,10847,8424],{},[595,10849,324],{},[591,10851,593],{},[595,10853,249],{},[591,10855,1508],{},[595,10857,10858],{},"36",[587,10860,607],{"mathvariant":606},[595,10862,3694],{},[591,10864,593],{},[595,10866,8697],{},[620,10868,10869],{"encoding":622},"R_5 = 1 + 36\u002F12 = 4.0",[568,10871,10873,10928,10946,10965],{"className":10872,"ariaHidden":628},[627],[568,10874,10876,10879,10919,10922,10925],{"className":10875},[632],[568,10877],{"className":10878,"style":4187},[636],[568,10880,10882,10885],{"className":10881},[641],[568,10883,8424],{"className":10884,"style":8459},[641,642],[568,10886,10888],{"className":10887},[4197],[568,10889,10891,10911],{"className":10890},[880,881],[568,10892,10894,10908],{"className":10893},[885],[568,10895,10897],{"className":10896,"style":10008},[889],[568,10898,10899,10902],{"style":8475},[568,10900],{"className":10901,"style":4214},[897],[568,10903,10905],{"className":10904},[902,903,904,905],[568,10906,324],{"className":10907},[641,905],[568,10909,942],{"className":10910},[941],[568,10912,10914],{"className":10913},[885],[568,10915,10917],{"className":10916,"style":4245},[889],[568,10918],{},[568,10920],{"className":10921,"style":648},[647],[568,10923,593],{"className":10924},[652],[568,10926],{"className":10927,"style":648},[647],[568,10929,10931,10934,10937,10940,10943],{"className":10930},[632],[568,10932],{"className":10933,"style":1249},[636],[568,10935,249],{"className":10936},[641],[568,10938],{"className":10939,"style":1256},[647],[568,10941,1508],{"className":10942},[1260],[568,10944],{"className":10945,"style":1256},[647],[568,10947,10949,10952,10956,10959,10962],{"className":10948},[632],[568,10950],{"className":10951,"style":662},[636],[568,10953,10955],{"className":10954},[641],"36\u002F12",[568,10957],{"className":10958,"style":648},[647],[568,10960,593],{"className":10961},[652],[568,10963],{"className":10964,"style":648},[647],[568,10966,10968,10971],{"className":10967},[632],[568,10969],{"className":10970,"style":691},[636],[568,10972,8697],{"className":10973},[641],[33,10975,10523,10976,10978,10979,10982],{},[563,10977,9900],{},"。J5 执行 12 分钟，结束时间为 ",[563,10980,10981],{},"11:30","。J5 周转时间 = 48分。",[33,10984,10985,10987,10988],{},[563,10986,10981],{},"，J3, J4 继续竞争：\n",[30,10989,10990,11135,11281],{},[33,10991,10992,10993],{},"J3 等待 = 60分。",[568,10994,10996,11031],{"className":10995},[571],[568,10997,10999],{"className":10998},[575],[577,11000,11001],{"xmlns":579},[581,11002,11003,11028],{},[584,11004,11005,11011,11013,11015,11017,11019,11021,11023,11025],{},[4138,11006,11007,11009],{},[587,11008,8424],{},[595,11010,287],{},[591,11012,593],{},[595,11014,249],{},[591,11016,1508],{},[595,11018,3352],{},[587,11020,607],{"mathvariant":606},[595,11022,10120],{},[591,11024,593],{},[595,11026,11027],{},"3.5",[620,11029,11030],{"encoding":622},"R_3 = 1 + 60\u002F24 = 3.5",[568,11032,11034,11089,11107,11126],{"className":11033,"ariaHidden":628},[627],[568,11035,11037,11040,11080,11083,11086],{"className":11036},[632],[568,11038],{"className":11039,"style":4187},[636],[568,11041,11043,11046],{"className":11042},[641],[568,11044,8424],{"className":11045,"style":8459},[641,642],[568,11047,11049],{"className":11048},[4197],[568,11050,11052,11072],{"className":11051},[880,881],[568,11053,11055,11069],{"className":11054},[885],[568,11056,11058],{"className":11057,"style":10008},[889],[568,11059,11060,11063],{"style":8475},[568,11061],{"className":11062,"style":4214},[897],[568,11064,11066],{"className":11065},[902,903,904,905],[568,11067,287],{"className":11068},[641,905],[568,11070,942],{"className":11071},[941],[568,11073,11075],{"className":11074},[885],[568,11076,11078],{"className":11077,"style":4245},[889],[568,11079],{},[568,11081],{"className":11082,"style":648},[647],[568,11084,593],{"className":11085},[652],[568,11087],{"className":11088,"style":648},[647],[568,11090,11092,11095,11098,11101,11104],{"className":11091},[632],[568,11093],{"className":11094,"style":1249},[636],[568,11096,249],{"className":11097},[641],[568,11099],{"className":11100,"style":1256},[647],[568,11102,1508],{"className":11103},[1260],[568,11105],{"className":11106,"style":1256},[647],[568,11108,11110,11113,11117,11120,11123],{"className":11109},[632],[568,11111],{"className":11112,"style":662},[636],[568,11114,11116],{"className":11115},[641],"60\u002F24",[568,11118],{"className":11119,"style":648},[647],[568,11121,593],{"className":11122},[652],[568,11124],{"className":11125,"style":648},[647],[568,11127,11129,11132],{"className":11128},[632],[568,11130],{"className":11131,"style":691},[636],[568,11133,11027],{"className":11134},[641],[33,11136,11137,11138],{},"J4 等待 = 54分。",[568,11139,11141,11177],{"className":11140},[571],[568,11142,11144],{"className":11143},[575],[577,11145,11146],{"xmlns":579},[581,11147,11148,11174],{},[584,11149,11150,11156,11158,11160,11162,11165,11167,11169,11171],{},[4138,11151,11152,11154],{},[587,11153,8424],{},[595,11155,306],{},[591,11157,593],{},[595,11159,249],{},[591,11161,1508],{},[595,11163,11164],{},"54",[587,11166,607],{"mathvariant":606},[595,11168,10120],{},[591,11170,593],{},[595,11172,11173],{},"3.25",[620,11175,11176],{"encoding":622},"R_4 = 1 + 54\u002F24 = 3.25",[568,11178,11180,11235,11253,11272],{"className":11179,"ariaHidden":628},[627],[568,11181,11183,11186,11226,11229,11232],{"className":11182},[632],[568,11184],{"className":11185,"style":4187},[636],[568,11187,11189,11192],{"className":11188},[641],[568,11190,8424],{"className":11191,"style":8459},[641,642],[568,11193,11195],{"className":11194},[4197],[568,11196,11198,11218],{"className":11197},[880,881],[568,11199,11201,11215],{"className":11200},[885],[568,11202,11204],{"className":11203,"style":10008},[889],[568,11205,11206,11209],{"style":8475},[568,11207],{"className":11208,"style":4214},[897],[568,11210,11212],{"className":11211},[902,903,904,905],[568,11213,306],{"className":11214},[641,905],[568,11216,942],{"className":11217},[941],[568,11219,11221],{"className":11220},[885],[568,11222,11224],{"className":11223,"style":4245},[889],[568,11225],{},[568,11227],{"className":11228,"style":648},[647],[568,11230,593],{"className":11231},[652],[568,11233],{"className":11234,"style":648},[647],[568,11236,11238,11241,11244,11247,11250],{"className":11237},[632],[568,11239],{"className":11240,"style":1249},[636],[568,11242,249],{"className":11243},[641],[568,11245],{"className":11246,"style":1256},[647],[568,11248,1508],{"className":11249},[1260],[568,11251],{"className":11252,"style":1256},[647],[568,11254,11256,11259,11263,11266,11269],{"className":11255},[632],[568,11257],{"className":11258,"style":662},[636],[568,11260,11262],{"className":11261},[641],"54\u002F24",[568,11264],{"className":11265,"style":648},[647],[568,11267,593],{"className":11268},[652],[568,11270],{"className":11271,"style":648},[647],[568,11273,11275,11278],{"className":11274},[632],[568,11276],{"className":11277,"style":691},[636],[568,11279,11173],{"className":11280},[641],[33,11282,10523,11283,11285,11286,11289],{},[563,11284,9461],{},"。J3 执行 24 分钟，结束时间为 ",[563,11287,11288],{},"11:54","。J3 周转时间 = 84分。",[33,11291,11292,11294,11295,11297,11298,11301],{},[563,11293,11288],{},"，",[563,11296,9475],{}," 开始执行。J4 执行 24 分钟，结束时间为 ",[563,11299,11300],{},"12:18","。J4 周转时间 = 102分。",[26,11303,11304,11307],{},[563,11305,11306],{},"执行顺序","：J1 → J2 → J5 → J3 → J4",[26,11309,11310,11313,11314,701],{},[563,11311,11312],{},"平均周转时间","：",[568,11315,11317,11376],{"className":11316},[571],[568,11318,11320],{"className":11319},[575],[577,11321,11322],{"xmlns":579},[581,11323,11324,11373],{},[584,11325,11326,11328,11330,11332,11335,11337,11340,11342,11345,11347,11349,11351,11353,11355,11357,11360,11362,11364,11366],{},[591,11327,1062],{"stretchy":1061},[595,11329,10712],{},[591,11331,1508],{},[595,11333,11334],{},"59",[591,11336,1508],{},[595,11338,11339],{},"84",[591,11341,1508],{},[595,11343,11344],{},"102",[591,11346,1508],{},[595,11348,10567],{},[591,11350,1071],{"stretchy":1061},[587,11352,607],{"mathvariant":606},[595,11354,324],{},[591,11356,593],{},[595,11358,11359],{},"335",[587,11361,607],{"mathvariant":606},[595,11363,324],{},[591,11365,593],{},[584,11367,11368,11371],{},[595,11369,11370],{"mathvariant":2397},"67",[5627,11372,7567],{},[620,11374,11375],{"encoding":622},"(42 + 59 + 84 + 102 + 48) \u002F 5 = 335 \u002F 5 = \\mathbf{67 \\text{ 分钟}}",[568,11377,11379,11400,11418,11436,11454,11479,11498],{"className":11378,"ariaHidden":628},[627],[568,11380,11382,11385,11388,11391,11394,11397],{"className":11381},[632],[568,11383],{"className":11384,"style":662},[636],[568,11386,1062],{"className":11387},[872],[568,11389,10712],{"className":11390},[641],[568,11392],{"className":11393,"style":1256},[647],[568,11395,1508],{"className":11396},[1260],[568,11398],{"className":11399,"style":1256},[647],[568,11401,11403,11406,11409,11412,11415],{"className":11402},[632],[568,11404],{"className":11405,"style":1249},[636],[568,11407,11334],{"className":11408},[641],[568,11410],{"className":11411,"style":1256},[647],[568,11413,1508],{"className":11414},[1260],[568,11416],{"className":11417,"style":1256},[647],[568,11419,11421,11424,11427,11430,11433],{"className":11420},[632],[568,11422],{"className":11423,"style":1249},[636],[568,11425,11339],{"className":11426},[641],[568,11428],{"className":11429,"style":1256},[647],[568,11431,1508],{"className":11432},[1260],[568,11434],{"className":11435,"style":1256},[647],[568,11437,11439,11442,11445,11448,11451],{"className":11438},[632],[568,11440],{"className":11441,"style":1249},[636],[568,11443,11344],{"className":11444},[641],[568,11446],{"className":11447,"style":1256},[647],[568,11449,1508],{"className":11450},[1260],[568,11452],{"className":11453,"style":1256},[647],[568,11455,11457,11460,11463,11466,11470,11473,11476],{"className":11456},[632],[568,11458],{"className":11459,"style":662},[636],[568,11461,10567],{"className":11462},[641],[568,11464,1071],{"className":11465},[955],[568,11467,11469],{"className":11468},[641],"\u002F5",[568,11471],{"className":11472,"style":648},[647],[568,11474,593],{"className":11475},[652],[568,11477],{"className":11478,"style":648},[647],[568,11480,11482,11485,11489,11492,11495],{"className":11481},[632],[568,11483],{"className":11484,"style":662},[636],[568,11486,11488],{"className":11487},[641],"335\u002F5",[568,11490],{"className":11491,"style":648},[647],[568,11493,593],{"className":11494},[652],[568,11496],{"className":11497,"style":648},[647],[568,11499,11501,11504],{"className":11500},[632],[568,11502],{"className":11503,"style":637},[636],[568,11505,11507,11510],{"className":11506},[641],[568,11508,11370],{"className":11509},[641,2676],[568,11511,11513,11516],{"className":11512},[641,6168],[568,11514,6415],{"className":11515},[641],[568,11517,7732],{"className":11518},[641,6419],[26,11520,11521,11523],{},[563,11522,9622],{}," 内存 100K 是一个干扰信息！题目明确\"按单道方式运行\"，不需要考虑内存分配并发情况。\n:::",[13,11525,11527],{"id":11526},"_36-银行家算法三类资源abc五进程","36. 银行家算法：三类资源（A\u002FB\u002FC）、五进程",[26,11529,11530],{},"设系统中资源类集合为 {A，B，C}，资源类 A 中含有 10 个资源实例，B 中含有 5 个，C 中含有 7 个。在 T0 时刻状态如下：",[53,11532,11533,11551],{},[56,11534,11535],{},[59,11536,11537,11539,11542,11545,11548],{},[62,11538,65],{"align":64},[62,11540,11541],{"align":64},"Max (A,B,C)",[62,11543,11544],{"align":64},"Allocation (A,B,C)",[62,11546,11547],{"align":64},"Need (A,B,C)",[62,11549,11550],{"align":64},"Available (A,B,C)",[73,11552,11553,11570,11584,11599,11613],{},[59,11554,11555,11558,11561,11564,11567],{},[78,11556,11557],{"align":64},"P0",[78,11559,11560],{"align":64},"(7, 5, 3)",[78,11562,11563],{"align":64},"(0, 1, 0)",[78,11565,11566],{"align":64},"(7, 4, 3)",[78,11568,11569],{"align":64},"(3, 3, 2)",[59,11571,11572,11574,11576,11579,11582],{},[78,11573,80],{"align":64},[78,11575,401],{"align":64},[78,11577,11578],{"align":64},"(2, 0, 0)",[78,11580,11581],{"align":64},"(1, 2, 2)",[78,11583],{"align":64},[59,11585,11586,11588,11591,11594,11597],{},[78,11587,90],{"align":64},[78,11589,11590],{"align":64},"(9, 0, 2)",[78,11592,11593],{"align":64},"(3, 0, 2)",[78,11595,11596],{"align":64},"(6, 0, 0)",[78,11598],{"align":64},[59,11600,11601,11603,11606,11608,11611],{},[78,11602,101],{"align":64},[78,11604,11605],{"align":64},"(2, 2, 2)",[78,11607,424],{"align":64},[78,11609,11610],{"align":64},"(0, 1, 1)",[78,11612],{"align":64},[59,11614,11615,11617,11620,11622,11625],{},[78,11616,112],{"align":64},[78,11618,11619],{"align":64},"(4, 3, 3)",[78,11621,434],{"align":64},[78,11623,11624],{"align":64},"(4, 3, 1)",[78,11626],{"align":64},[30,11628,11629,11635],{},[33,11630,11631,11632,11634],{},"(1) 假如现在进程 P1 发出新的资源申请 Request",[568,11633,249],{},"=(1,0,2)，系统是否可以实施资源分配，为什么？",[33,11636,11637],{},"(2) 在上面新状态下，对于进程 P0 所发出的资源请求（0, 2, 0）系统是否能实施资源分配？要求写出计算步骤及过程。",[26,11639,41],{},[554,11641,3076],{"id":11642},"答案与详细解答-9",[26,11644,11645],{},[563,11646,11647],{},"(1) P1 申请 (1, 0, 2)",[9640,11649,11650,11685,11717,11733],{},[33,11651,11652,11653,11684],{},"检查合法性：Request (1,0,2) ",[568,11654,11656,11671],{"className":11655},[571],[568,11657,11659],{"className":11658},[575],[577,11660,11661],{"xmlns":579},[581,11662,11663,11668],{},[584,11664,11665],{},[591,11666,11667],{},"≤",[620,11669,11670],{"encoding":622},"\\le",[568,11672,11674],{"className":11673,"ariaHidden":628},[627],[568,11675,11677,11681],{"className":11676},[632],[568,11678],{"className":11679,"style":11680},[636],"height:0.7719em;vertical-align:-0.136em;",[568,11682,11667],{"className":11683},[652]," P1 Need (1,2,2) 成立。",[33,11686,11687,11688,11716],{},"检查可用性：Request (1,0,2) ",[568,11689,11691,11704],{"className":11690},[571],[568,11692,11694],{"className":11693},[575],[577,11695,11696],{"xmlns":579},[581,11697,11698,11702],{},[584,11699,11700],{},[591,11701,11667],{},[620,11703,11670],{"encoding":622},[568,11705,11707],{"className":11706,"ariaHidden":628},[627],[568,11708,11710,11713],{"className":11709},[632],[568,11711],{"className":11712,"style":11680},[636],[568,11714,11667],{"className":11715},[652]," Available (3,3,2) 成立。",[33,11718,11719,11722],{},[563,11720,11721],{},"试探分配后的新状态：",[30,11723,11724,11730],{},[33,11725,11726,11727],{},"Available = (3,3,2) - (1,0,2) = ",[563,11728,11729],{},"(2, 3, 0)",[33,11731,11732],{},"P1 Allocation = (3, 0, 2)，P1 Need = (0, 2, 0)",[33,11734,11735,11738,11739],{},[563,11736,11737],{},"安全性检查","（Available=(2,3,0)）：\nP1 Need=(0,2,0) 满足，P1 执行完释放，Available=(5,3,2)。\n后续可满足 P3 → P4 → P0 → P2。\n",[563,11740,11741],{},"结论：存在安全序列（P1→P3→P4→P0→P2），可以实施资源分配。",[26,11743,11744],{},[563,11745,11746],{},"(2) 随后 P0 请求 (0, 2, 0)",[9640,11748,11749,11754,11815,11830],{},[33,11750,11751,11752,701],{},"在上述新状态下，Available = ",[563,11753,11729],{},[33,11755,11756,11757,11785,11786,11814],{},"检查：Request ",[568,11758,11760,11773],{"className":11759},[571],[568,11761,11763],{"className":11762},[575],[577,11764,11765],{"xmlns":579},[581,11766,11767,11771],{},[584,11768,11769],{},[591,11770,11667],{},[620,11772,11670],{"encoding":622},[568,11774,11776],{"className":11775,"ariaHidden":628},[627],[568,11777,11779,11782],{"className":11778},[632],[568,11780],{"className":11781,"style":11680},[636],[568,11783,11667],{"className":11784},[652]," P0 Need 成立；Request ",[568,11787,11789,11802],{"className":11788},[571],[568,11790,11792],{"className":11791},[575],[577,11793,11794],{"xmlns":579},[581,11795,11796,11800],{},[584,11797,11798],{},[591,11799,11667],{},[620,11801,11670],{"encoding":622},[568,11803,11805],{"className":11804,"ariaHidden":628},[627],[568,11806,11808,11811],{"className":11807},[632],[568,11809],{"className":11810,"style":11680},[636],[568,11812,11667],{"className":11813},[652]," Available 成立。",[33,11816,11817,11819],{},[563,11818,11721],{},[30,11820,11821,11827],{},[33,11822,11823,11824],{},"Available = (2,3,0) - (0,2,0) = ",[563,11825,11826],{},"(2, 1, 0)",[33,11828,11829],{},"P0 Allocation = (0,3,0)，P0 Need = (7,2,3)",[33,11831,11832,11834,11835,2349,11838],{},[563,11833,11737],{},"（Available=(2,1,0)）：\n检查所有进程当前的 Need：没有任何一个进程的 Need 可以被 (2,1,0) 满足，无法找到安全序列，陷入",[563,11836,11837],{},"不安全状态",[563,11839,11840],{},"结论：拒绝分配，P0 必须等待。",[26,11842,11843,11845,11846,11849,11850,11853],{},[563,11844,9622],{}," 许多人在第二步忘了把 Available 基础值更新为第一步算完的 ",[1658,11847,11848],{},"(2,3,0)","，而是继续拿最初的 ",[1658,11851,11852],{},"(3,3,2)"," 去算。\n:::",[13,11855,11857],{"id":11856},"_37-位示图字号和位号计算","37. 位示图：字号和位号计算",[26,11859,11860],{},"现有一台 16 位字长的专用机，采用页式存储管理。主存储器共有 4096 块 (块号为 0～4095)，现用位示图分配主存空间。试问：",[30,11862,11863,11866,11869],{},[33,11864,11865],{},"(1) 该位示图占用几个字?",[33,11867,11868],{},"(2) 主存块号 3999 对应位示图的字号和位号 (均从 0 开始) 各是多少?",[33,11870,11871],{},"(3) 位示图字号 199，位号 9 对应主存的块号是多少?",[26,11873,41],{},[554,11875,3076],{"id":11876},"答案与详细解答-10",[26,11878,11879],{},[563,11880,11881],{},"(1) 位示图占用几个字？",[26,11883,11884,11885,11963],{},"共有 4096 个块，需要 4096 个 Bit。机器字长为 16 位，每个 Word 有 16 个 Bit。\n佔用字数 = ",[568,11886,11888,11912],{"className":11887},[571],[568,11889,11891],{"className":11890},[575],[577,11892,11893],{"xmlns":579},[581,11894,11895,11909],{},[584,11896,11897,11900,11902,11905,11907],{},[595,11898,11899],{},"4096",[591,11901,9662],{},[595,11903,11904],{},"16",[591,11906,593],{},[595,11908,7981],{"mathvariant":2397},[620,11910,11911],{"encoding":622},"4096 \\div 16 = \\mathbf{256}",[568,11913,11915,11933,11951],{"className":11914,"ariaHidden":628},[627],[568,11916,11918,11921,11924,11927,11930],{"className":11917},[632],[568,11919],{"className":11920,"style":1249},[636],[568,11922,11899],{"className":11923},[641],[568,11925],{"className":11926,"style":1256},[647],[568,11928,9662],{"className":11929},[1260],[568,11931],{"className":11932,"style":1256},[647],[568,11934,11936,11939,11942,11945,11948],{"className":11935},[632],[568,11937],{"className":11938,"style":691},[636],[568,11940,11904],{"className":11941},[641],[568,11943],{"className":11944,"style":648},[647],[568,11946,593],{"className":11947},[652],[568,11949],{"className":11950,"style":648},[647],[568,11952,11954,11957],{"className":11953},[632],[568,11955],{"className":11956,"style":691},[636],[568,11958,11960],{"className":11959},[641],[568,11961,7981],{"className":11962},[641,2676]," 个字。",[26,11965,11966],{},[563,11967,11968],{},"(2) 块号 3999 对应的字号和位号？",[26,11970,11971,11972,12062,12063,701],{},"字号 = ",[568,11973,11975,12005],{"className":11974},[571],[568,11976,11978],{"className":11977},[575],[577,11979,11980],{"xmlns":579},[581,11981,11982,12002],{},[584,11983,11984,11987,11990,11992,11994,11997,11999],{},[591,11985,11986],{"stretchy":1061},"⌊",[595,11988,11989],{},"3999",[591,11991,9662],{},[595,11993,11904],{},[591,11995,11996],{"stretchy":1061},"⌋",[591,11998,593],{},[595,12000,12001],{"mathvariant":2397},"249",[620,12003,12004],{"encoding":622},"\\lfloor 3999 \\div 16 \\rfloor = \\mathbf{249}",[568,12006,12008,12029,12050],{"className":12007,"ariaHidden":628},[627],[568,12009,12011,12014,12017,12020,12023,12026],{"className":12010},[632],[568,12012],{"className":12013,"style":662},[636],[568,12015,11986],{"className":12016},[872],[568,12018,11989],{"className":12019},[641],[568,12021],{"className":12022,"style":1256},[647],[568,12024,9662],{"className":12025},[1260],[568,12027],{"className":12028,"style":1256},[647],[568,12030,12032,12035,12038,12041,12044,12047],{"className":12031},[632],[568,12033],{"className":12034,"style":662},[636],[568,12036,11904],{"className":12037},[641],[568,12039,11996],{"className":12040},[955],[568,12042],{"className":12043,"style":648},[647],[568,12045,593],{"className":12046},[652],[568,12048],{"className":12049,"style":648},[647],[568,12051,12053,12056],{"className":12052},[632],[568,12054],{"className":12055,"style":691},[636],[568,12057,12059],{"className":12058},[641],[568,12060,12001],{"className":12061},[641,2676],"。\n位号 = ",[568,12064,12066,12104],{"className":12065},[571],[568,12067,12069],{"className":12068},[575],[577,12070,12071],{"xmlns":579},[581,12072,12073,12101],{},[584,12074,12075,12077,12080,12092,12094,12096,12098],{},[595,12076,11989],{},[5627,12078,12079],{}," ",[591,12081,12083],{"lspace":12082,"rspace":12082},"0.22em",[584,12084,12085,12087,12090],{},[587,12086,600],{"mathvariant":606},[587,12088,12089],{"mathvariant":606},"o",[587,12091,4732],{"mathvariant":606},[5627,12093,12079],{},[595,12095,11904],{},[591,12097,593],{},[595,12099,12100],{"mathvariant":2397},"15",[620,12102,12103],{"encoding":622},"3999 \\bmod 16 = \\mathbf{15}",[568,12105,12107,12140,12158],{"className":12106,"ariaHidden":628},[627],[568,12108,12110,12113,12116,12120,12123,12134,12137],{"className":12109},[632],[568,12111],{"className":12112,"style":6624},[636],[568,12114,11989],{"className":12115},[641],[568,12117],{"className":12118,"style":12119},[647],"margin-right:0.0556em;",[568,12121],{"className":12122,"style":1256},[647],[568,12124,12126],{"className":12125},[1260],[568,12127,12129],{"className":12128},[641],[568,12130,12133],{"className":12131},[641,12132],"mathrm","mod",[568,12135],{"className":12136,"style":12119},[647],[568,12138],{"className":12139,"style":1256},[647],[568,12141,12143,12146,12149,12152,12155],{"className":12142},[632],[568,12144],{"className":12145,"style":691},[636],[568,12147,11904],{"className":12148},[641],[568,12150],{"className":12151,"style":648},[647],[568,12153,593],{"className":12154},[652],[568,12156],{"className":12157,"style":648},[647],[568,12159,12161,12164],{"className":12160},[632],[568,12162],{"className":12163,"style":691},[636],[568,12165,12167],{"className":12166},[641],[568,12168,12100],{"className":12169},[641,2676],[26,12171,12172],{},[563,12173,12174],{},"(3) 字号 199，位号 9 对应的主存块号？",[26,12176,12177,12178,701],{},"块号 = ",[568,12179,12181,12232],{"className":12180},[571],[568,12182,12184],{"className":12183},[575],[577,12185,12186],{"xmlns":579},[581,12187,12188,12229],{},[584,12189,12190,12193,12195,12197,12199,12202,12204,12207,12209,12211,12213,12215,12217,12220,12222,12224,12226],{},[5627,12191,12192],{},"字号",[591,12194,1221],{},[595,12196,11904],{},[591,12198,1508],{},[5627,12200,12201],{},"位号",[591,12203,593],{},[595,12205,12206],{},"199",[591,12208,1221],{},[595,12210,11904],{},[591,12212,1508],{},[595,12214,735],{},[591,12216,593],{},[595,12218,12219],{},"3184",[591,12221,1508],{},[595,12223,735],{},[591,12225,593],{},[595,12227,12228],{"mathvariant":2397},"3193",[620,12230,12231],{"encoding":622},"\\text{字号} \\times 16 + \\text{位号} = 199 \\times 16 + 9 = 3184 + 9 = \\mathbf{3193}",[568,12233,12235,12256,12274,12295,12313,12331,12349,12367,12385],{"className":12234,"ariaHidden":628},[627],[568,12236,12238,12241,12247,12250,12253],{"className":12237},[632],[568,12239],{"className":12240,"style":4684},[636],[568,12242,12244],{"className":12243},[641,6168],[568,12245,12192],{"className":12246},[641,6419],[568,12248],{"className":12249,"style":1256},[647],[568,12251,1221],{"className":12252},[1260],[568,12254],{"className":12255,"style":1256},[647],[568,12257,12259,12262,12265,12268,12271],{"className":12258},[632],[568,12260],{"className":12261,"style":1249},[636],[568,12263,11904],{"className":12264},[641],[568,12266],{"className":12267,"style":1256},[647],[568,12269,1508],{"className":12270},[1260],[568,12272],{"className":12273,"style":1256},[647],[568,12275,12277,12280,12286,12289,12292],{"className":12276},[632],[568,12278],{"className":12279,"style":637},[636],[568,12281,12283],{"className":12282},[641,6168],[568,12284,12201],{"className":12285},[641,6419],[568,12287],{"className":12288,"style":648},[647],[568,12290,593],{"className":12291},[652],[568,12293],{"className":12294,"style":648},[647],[568,12296,12298,12301,12304,12307,12310],{"className":12297},[632],[568,12299],{"className":12300,"style":1249},[636],[568,12302,12206],{"className":12303},[641],[568,12305],{"className":12306,"style":1256},[647],[568,12308,1221],{"className":12309},[1260],[568,12311],{"className":12312,"style":1256},[647],[568,12314,12316,12319,12322,12325,12328],{"className":12315},[632],[568,12317],{"className":12318,"style":1249},[636],[568,12320,11904],{"className":12321},[641],[568,12323],{"className":12324,"style":1256},[647],[568,12326,1508],{"className":12327},[1260],[568,12329],{"className":12330,"style":1256},[647],[568,12332,12334,12337,12340,12343,12346],{"className":12333},[632],[568,12335],{"className":12336,"style":691},[636],[568,12338,735],{"className":12339},[641],[568,12341],{"className":12342,"style":648},[647],[568,12344,593],{"className":12345},[652],[568,12347],{"className":12348,"style":648},[647],[568,12350,12352,12355,12358,12361,12364],{"className":12351},[632],[568,12353],{"className":12354,"style":1249},[636],[568,12356,12219],{"className":12357},[641],[568,12359],{"className":12360,"style":1256},[647],[568,12362,1508],{"className":12363},[1260],[568,12365],{"className":12366,"style":1256},[647],[568,12368,12370,12373,12376,12379,12382],{"className":12369},[632],[568,12371],{"className":12372,"style":691},[636],[568,12374,735],{"className":12375},[641],[568,12377],{"className":12378,"style":648},[647],[568,12380,593],{"className":12381},[652],[568,12383],{"className":12384,"style":648},[647],[568,12386,12388,12391],{"className":12387},[632],[568,12389],{"className":12390,"style":691},[636],[568,12392,12394],{"className":12393},[641],[568,12395,12228],{"className":12396},[641,2676],[26,12398,12399,12401],{},[563,12400,9622],{}," 注意题目强调\"均从 0 开始\"。如果从 1 开始，计算公式需要进行平移。\n:::",[13,12403,12405],{"id":12404},"_38-信号量同步数据采集-计算-输出三进程","38. 信号量同步：数据采集-计算-输出三进程",[26,12407,12408],{},"某数据处理系统由数据采集、数据计算和数据输出三个进程组成，采集进程把采集到的数据送入由 M 个缓冲块组成的输入缓冲区（每次向一个缓冲块送数据），计算进程从输入缓冲区取数据计算（每次取一个缓冲块的数据），并将计算结果送入到由 N 个缓冲块组成的输出缓冲区（每次向一个缓冲块送数据），输出进程每次从输出缓冲区取一个结果输出。编写利用信号量机制实现的三者之间同步算法，要求写出信号量的含义和初值。",[26,12410,41],{},[554,12412,3076],{"id":12413},"答案与详细解答-11",[26,12415,12416],{},"信号量定义：",[30,12418,12419,12425,12431,12437,12443,12449],{},[33,12420,12421,12424],{},[1658,12422,12423],{},"emptyM = M","：输入缓冲区的空位数。",[33,12426,12427,12430],{},[1658,12428,12429],{},"fullM = 0","：输入缓冲区中已有数据的数量。",[33,12432,12433,12436],{},[1658,12434,12435],{},"mutexM = 1","：对输入缓冲池进行互斥访问。",[33,12438,12439,12442],{},[1658,12440,12441],{},"emptyN = N","：输出缓冲区的空位数。",[33,12444,12445,12448],{},[1658,12446,12447],{},"fullN = 0","：输出缓冲区中已有结果的数量。",[33,12450,12451,12454],{},[1658,12452,12453],{},"mutexN = 1","：对输出缓冲池进行互斥访问。",[9308,12456,12459],{"className":12457,"code":12458,"language":4147,"meta":9315,"style":9315},"language-c shiki shiki-themes github-light github-dark","\u002F\u002F 采集进程 (Producer 1)\nwhile(true) {\n    采集数据;\n    wait(emptyM);    \u002F\u002F 申请输入缓冲区空位 (同步)\n    wait(mutexM);    \u002F\u002F 锁定输入缓冲区 (互斥)\n    将数据放入输入缓冲区;\n    signal(mutexM);  \u002F\u002F 解锁输入缓冲区\n    signal(fullM);   \u002F\u002F 通知输入缓冲区已有数据\n}\n\n\u002F\u002F 计算进程 (Consumer 1 & Producer 2)\nwhile(true) {\n    wait(fullM);     \u002F\u002F 等待输入缓冲区有数据\n    wait(mutexM);    \u002F\u002F 锁定输入缓冲区\n    从输入缓冲区取出数据;\n    signal(mutexM);\n    signal(emptyM);  \u002F\u002F 释放输入缓冲区空位\n\n    计算数据;\n\n    wait(emptyN);    \u002F\u002F 申请输出缓冲区空位\n    wait(mutexN);    \u002F\u002F 锁定输出缓冲区\n    将结果放入输出缓冲区;\n    signal(mutexN);\n    signal(fullN);   \u002F\u002F 通知输出缓冲区已有结果\n}\n\n\u002F\u002F 输出进程 (Consumer 2)\nwhile(true) {\n    wait(fullN);     \u002F\u002F 等待输出缓冲区有结果\n    wait(mutexN);    \u002F\u002F 锁定输出缓冲区\n    从输出缓冲区取出结果;\n    signal(mutexN);\n    signal(emptyN);  \u002F\u002F 释放输出缓冲区空位\n    \n    输出结果;\n}\n",[1658,12460,12461,12468,12474,12480,12486,12492,12498,12504,12510,12516,12523,12529,12534,12540,12546,12552,12558,12564,12569,12575,12580,12586,12592,12598,12604,12610,12615,12620,12626,12631,12637,12642,12648,12653,12659,12665,12671],{"__ignoreMap":9315},[568,12462,12465],{"class":12463,"line":12464},"line",1,[568,12466,12467],{},"\u002F\u002F 采集进程 (Producer 1)\n",[568,12469,12471],{"class":12463,"line":12470},2,[568,12472,12473],{},"while(true) {\n",[568,12475,12477],{"class":12463,"line":12476},3,[568,12478,12479],{},"    采集数据;\n",[568,12481,12483],{"class":12463,"line":12482},4,[568,12484,12485],{},"    wait(emptyM);    \u002F\u002F 申请输入缓冲区空位 (同步)\n",[568,12487,12489],{"class":12463,"line":12488},5,[568,12490,12491],{},"    wait(mutexM);    \u002F\u002F 锁定输入缓冲区 (互斥)\n",[568,12493,12495],{"class":12463,"line":12494},6,[568,12496,12497],{},"    将数据放入输入缓冲区;\n",[568,12499,12501],{"class":12463,"line":12500},7,[568,12502,12503],{},"    signal(mutexM);  \u002F\u002F 解锁输入缓冲区\n",[568,12505,12507],{"class":12463,"line":12506},8,[568,12508,12509],{},"    signal(fullM);   \u002F\u002F 通知输入缓冲区已有数据\n",[568,12511,12513],{"class":12463,"line":12512},9,[568,12514,12515],{},"}\n",[568,12517,12519],{"class":12463,"line":12518},10,[568,12520,12522],{"emptyLinePlaceholder":12521},true,"\n",[568,12524,12526],{"class":12463,"line":12525},11,[568,12527,12528],{},"\u002F\u002F 计算进程 (Consumer 1 & Producer 2)\n",[568,12530,12532],{"class":12463,"line":12531},12,[568,12533,12473],{},[568,12535,12537],{"class":12463,"line":12536},13,[568,12538,12539],{},"    wait(fullM);     \u002F\u002F 等待输入缓冲区有数据\n",[568,12541,12543],{"class":12463,"line":12542},14,[568,12544,12545],{},"    wait(mutexM);    \u002F\u002F 锁定输入缓冲区\n",[568,12547,12549],{"class":12463,"line":12548},15,[568,12550,12551],{},"    从输入缓冲区取出数据;\n",[568,12553,12555],{"class":12463,"line":12554},16,[568,12556,12557],{},"    signal(mutexM);\n",[568,12559,12561],{"class":12463,"line":12560},17,[568,12562,12563],{},"    signal(emptyM);  \u002F\u002F 释放输入缓冲区空位\n",[568,12565,12567],{"class":12463,"line":12566},18,[568,12568,12522],{"emptyLinePlaceholder":12521},[568,12570,12572],{"class":12463,"line":12571},19,[568,12573,12574],{},"    计算数据;\n",[568,12576,12578],{"class":12463,"line":12577},20,[568,12579,12522],{"emptyLinePlaceholder":12521},[568,12581,12583],{"class":12463,"line":12582},21,[568,12584,12585],{},"    wait(emptyN);    \u002F\u002F 申请输出缓冲区空位\n",[568,12587,12589],{"class":12463,"line":12588},22,[568,12590,12591],{},"    wait(mutexN);    \u002F\u002F 锁定输出缓冲区\n",[568,12593,12595],{"class":12463,"line":12594},23,[568,12596,12597],{},"    将结果放入输出缓冲区;\n",[568,12599,12601],{"class":12463,"line":12600},24,[568,12602,12603],{},"    signal(mutexN);\n",[568,12605,12607],{"class":12463,"line":12606},25,[568,12608,12609],{},"    signal(fullN);   \u002F\u002F 通知输出缓冲区已有结果\n",[568,12611,12613],{"class":12463,"line":12612},26,[568,12614,12515],{},[568,12616,12618],{"class":12463,"line":12617},27,[568,12619,12522],{"emptyLinePlaceholder":12521},[568,12621,12623],{"class":12463,"line":12622},28,[568,12624,12625],{},"\u002F\u002F 输出进程 (Consumer 2)\n",[568,12627,12629],{"class":12463,"line":12628},29,[568,12630,12473],{},[568,12632,12634],{"class":12463,"line":12633},30,[568,12635,12636],{},"    wait(fullN);     \u002F\u002F 等待输出缓冲区有结果\n",[568,12638,12640],{"class":12463,"line":12639},31,[568,12641,12591],{},[568,12643,12645],{"class":12463,"line":12644},32,[568,12646,12647],{},"    从输出缓冲区取出结果;\n",[568,12649,12651],{"class":12463,"line":12650},33,[568,12652,12603],{},[568,12654,12656],{"class":12463,"line":12655},34,[568,12657,12658],{},"    signal(emptyN);  \u002F\u002F 释放输出缓冲区空位\n",[568,12660,12662],{"class":12463,"line":12661},35,[568,12663,12664],{},"    \n",[568,12666,12668],{"class":12463,"line":12667},36,[568,12669,12670],{},"    输出结果;\n",[568,12672,12674],{"class":12463,"line":12673},37,[568,12675,12515],{},[26,12677,12678,1656,12680,12683,12684,12687],{},[563,12679,9622],{},[1658,12681,12682],{},"wait(互斥信号量)"," 和 ",[1658,12685,12686],{},"wait(同步信号量)"," 的顺序不能颠倒！必须先同步（申请资源 empty\u002Ffull），再互斥（锁定 mutex），否则会导致死锁。\n:::",[13,12689,12691],{"id":12690},"_39-文件系统设计60g-磁盘商用-io","39. 文件系统设计：60G 磁盘、商用 I\u002FO",[26,12693,12694],{},"假定你负责设计一个基于 32 位计算机的文件系统，如果存储磁盘的容量是 60G，磁盘扇区大小为 1M，文件的最大容量为 2GB，文件名仅支持 8.3 格式。该文件系统主要满足商用 I\u002FO 操作，因此空间变化比较频繁，请设计一种合理的文件系统磁盘空间管理方式。包括目录、文件的逻辑结构与物理实现。",[26,12696,41],{},[554,12698,3076],{"id":12699},"答案与详细解答-12",[30,12701,12702,12716,12729,12739],{},[33,12703,12704,12707,12708,12711,12712,12715],{},[563,12705,12706],{},"物理实现 (Physical Structure)：","\n因为空间变化频繁，动态扩容要求高，应采用",[563,12709,12710],{},"索引分配 (Indexed Allocation)","。\n磁盘块大小为 1MB，最大文件 2GB，代表一个文件最多占用 2048 个块。一个索引块完全可以装得下这 2048 个指针，因此采用",[563,12713,12714],{},"单级索引","结构即可。",[33,12717,12718,12721,12722,12725,12726,701],{},[563,12719,12720],{},"逻辑结构 (Logical Structure)：","\n因为主要满足商用 I\u002FO，这类场景通常涉及数据库和结构化查询，应该采用",[563,12723,12724],{},"有结构文件（记录式文件）","，为了加速查询，设计为",[563,12727,12728],{},"索引顺序文件",[33,12730,12731,12734,12735,12738],{},[563,12732,12733],{},"磁盘空间管理 (Free Space Management)：","\n总块数 = 60GB \u002F 1MB = 60,000 块。\n可以使用",[563,12736,12737],{},"位示图 (Bit map)"," 来管理空闲块。只有 60,000 块，位示图仅需约 7.5 KB 的空间，可以常驻内存，提供极高的分配效率。",[33,12740,12741,12744,12745,12748,12749,12752],{},[563,12742,12743],{},"目录结构 (Directory Structure)：","\n采用",[563,12746,12747],{},"多级树状目录结构 (Tree-structured Directory)","。\n由于只支持 8.3 格式（文件名 8 字符 + 扩展名 3 字符，共 11 bytes），目录项可以设计为包含 ",[1658,12750,12751],{},"11 Bytes文件名 + 4 Bytes索引节点\u002F首块指针"," 等简洁结构。",[26,12754,12755,12757],{},[563,12756,9622],{}," 不要盲目写多级索引。这里块大小有 1MB 那么大，一个块装几万个指针绰绰有余，完全不需要 UNIX 那种多层间接索引。\n:::",[13,12759,12761],{"id":12760},"_40-信号量同步readmoveprint-三进程单容量缓冲","40. 信号量同步：read\u002Fmove\u002Fprint 三进程单容量缓冲",[26,12763,12764],{},"假定系统有三个并发进程 read, move 和 print 共享缓冲器 B1 和 B2。进程 read 负责从输入设备上读信息，每读出一个记录后把它存放到缓冲器 B1 中。进程 move 从缓冲器 B1 中取出一记录，加工后存入缓冲器 B2。进程 print 将 B2 中的记录取出打印输出。缓冲器 B1 和 B2 每次只能存放一个记录。要求三个进程协调完成任务，使打印出来的与读入的记录的个数，次序完全一样。请用 wait 和 signal 原语写出它们的并发程序。",[26,12766,41],{},[554,12768,3076],{"id":12769},"答案与详细解答-13",[26,12771,12772],{},"由于 B1 和 B2 的容量都严格为 1，为每个缓冲区定义一对同步信号量：",[30,12774,12775,12781,12787,12793],{},[33,12776,12777,12780],{},[1658,12778,12779],{},"empty1 = 1","：B1 的空位数。",[33,12782,12783,12786],{},[1658,12784,12785],{},"full1 = 0","：B1 的数据数。",[33,12788,12789,12792],{},[1658,12790,12791],{},"empty2 = 1","：B2 的空位数。",[33,12794,12795,12798],{},[1658,12796,12797],{},"full2 = 0","：B2 的数据数。",[9308,12800,12802],{"className":12457,"code":12801,"language":4147,"meta":9315,"style":9315},"\u002F\u002F 读入进程\nvoid read_process() {\n    while(true) {\n        读入一个记录 info;\n        wait(empty1);      \u002F\u002F 确保 B1 为空\n        将 info 存入 B1;\n        signal(full1);     \u002F\u002F 通知 move 进程 B1 已有数据\n    }\n}\n\n\u002F\u002F 搬运\u002F加工进程\nvoid move_process() {\n    while(true) {\n        wait(full1);       \u002F\u002F 确保 B1 有数据\n        从 B1 取出记录 info;\n        signal(empty1);    \u002F\u002F 释放 B1\n\n        加工 info;\n\n        wait(empty2);      \u002F\u002F 确保 B2 为空\n        将 info 存入 B2;\n        signal(full2);     \u002F\u002F 通知 print 进程 B2 已有数据\n    }\n}\n\n\u002F\u002F 打印进程\nvoid print_process() {\n    while(true) {\n        wait(full2);       \u002F\u002F 确保 B2 有数据\n        从 B2 取出记录 info;\n        signal(empty2);    \u002F\u002F 释放 B2\n\n        打印 info;\n    }\n}\n",[1658,12803,12804,12809,12814,12819,12824,12829,12834,12839,12844,12848,12852,12857,12862,12866,12871,12876,12881,12885,12890,12894,12899,12904,12909,12913,12917,12921,12926,12931,12935,12940,12945,12950,12954,12959,12963],{"__ignoreMap":9315},[568,12805,12806],{"class":12463,"line":12464},[568,12807,12808],{},"\u002F\u002F 读入进程\n",[568,12810,12811],{"class":12463,"line":12470},[568,12812,12813],{},"void read_process() {\n",[568,12815,12816],{"class":12463,"line":12476},[568,12817,12818],{},"    while(true) {\n",[568,12820,12821],{"class":12463,"line":12482},[568,12822,12823],{},"        读入一个记录 info;\n",[568,12825,12826],{"class":12463,"line":12488},[568,12827,12828],{},"        wait(empty1);      \u002F\u002F 确保 B1 为空\n",[568,12830,12831],{"class":12463,"line":12494},[568,12832,12833],{},"        将 info 存入 B1;\n",[568,12835,12836],{"class":12463,"line":12500},[568,12837,12838],{},"        signal(full1);     \u002F\u002F 通知 move 进程 B1 已有数据\n",[568,12840,12841],{"class":12463,"line":12506},[568,12842,12843],{},"    }\n",[568,12845,12846],{"class":12463,"line":12512},[568,12847,12515],{},[568,12849,12850],{"class":12463,"line":12518},[568,12851,12522],{"emptyLinePlaceholder":12521},[568,12853,12854],{"class":12463,"line":12525},[568,12855,12856],{},"\u002F\u002F 搬运\u002F加工进程\n",[568,12858,12859],{"class":12463,"line":12531},[568,12860,12861],{},"void move_process() {\n",[568,12863,12864],{"class":12463,"line":12536},[568,12865,12818],{},[568,12867,12868],{"class":12463,"line":12542},[568,12869,12870],{},"        wait(full1);       \u002F\u002F 确保 B1 有数据\n",[568,12872,12873],{"class":12463,"line":12548},[568,12874,12875],{},"        从 B1 取出记录 info;\n",[568,12877,12878],{"class":12463,"line":12554},[568,12879,12880],{},"        signal(empty1);    \u002F\u002F 释放 B1\n",[568,12882,12883],{"class":12463,"line":12560},[568,12884,12522],{"emptyLinePlaceholder":12521},[568,12886,12887],{"class":12463,"line":12566},[568,12888,12889],{},"        加工 info;\n",[568,12891,12892],{"class":12463,"line":12571},[568,12893,12522],{"emptyLinePlaceholder":12521},[568,12895,12896],{"class":12463,"line":12577},[568,12897,12898],{},"        wait(empty2);      \u002F\u002F 确保 B2 为空\n",[568,12900,12901],{"class":12463,"line":12582},[568,12902,12903],{},"        将 info 存入 B2;\n",[568,12905,12906],{"class":12463,"line":12588},[568,12907,12908],{},"        signal(full2);     \u002F\u002F 通知 print 进程 B2 已有数据\n",[568,12910,12911],{"class":12463,"line":12594},[568,12912,12843],{},[568,12914,12915],{"class":12463,"line":12600},[568,12916,12515],{},[568,12918,12919],{"class":12463,"line":12606},[568,12920,12522],{"emptyLinePlaceholder":12521},[568,12922,12923],{"class":12463,"line":12612},[568,12924,12925],{},"\u002F\u002F 打印进程\n",[568,12927,12928],{"class":12463,"line":12617},[568,12929,12930],{},"void print_process() {\n",[568,12932,12933],{"class":12463,"line":12622},[568,12934,12818],{},[568,12936,12937],{"class":12463,"line":12628},[568,12938,12939],{},"        wait(full2);       \u002F\u002F 确保 B2 有数据\n",[568,12941,12942],{"class":12463,"line":12633},[568,12943,12944],{},"        从 B2 取出记录 info;\n",[568,12946,12947],{"class":12463,"line":12639},[568,12948,12949],{},"        signal(empty2);    \u002F\u002F 释放 B2\n",[568,12951,12952],{"class":12463,"line":12644},[568,12953,12522],{"emptyLinePlaceholder":12521},[568,12955,12956],{"class":12463,"line":12650},[568,12957,12958],{},"        打印 info;\n",[568,12960,12961],{"class":12463,"line":12655},[568,12962,12843],{},[568,12964,12965],{"class":12463,"line":12661},[568,12966,12515],{},[26,12968,12969,12971,12972,12975,12976,13021,13022,13024,13025,12683,13028,13031],{},[563,12970,9622],{}," 画蛇添足加上 ",[1658,12973,12974],{},"mutex","。当缓冲区大小 ",[568,12977,12979,12996],{"className":12978},[571],[568,12980,12982],{"className":12981},[575],[577,12983,12984],{"xmlns":579},[581,12985,12986,12993],{},[584,12987,12988,12991],{},[591,12989,12990],{},">",[595,12992,249],{},[620,12994,12995],{"encoding":622},">1",[568,12997,12999,13012],{"className":12998,"ariaHidden":628},[627],[568,13000,13002,13006,13009],{"className":13001},[632],[568,13003],{"className":13004,"style":13005},[636],"height:0.5782em;vertical-align:-0.0391em;",[568,13007,12990],{"className":13008},[652],[568,13010],{"className":13011,"style":648},[647],[568,13013,13015,13018],{"className":13014},[632],[568,13016],{"className":13017,"style":691},[636],[568,13019,249],{"className":13020},[641]," 或存在多个竞争者时才必须加上 ",[1658,13023,12974],{},"。对于严格的一对一且容量为 1 的通道，",[1658,13026,13027],{},"empty",[1658,13029,13030],{},"full"," 的 0\u002F1 切换本身就是完美的互斥锁。\n:::",[13,13033,13035],{"id":13034},"_41-磁道调度fcfs-sstf-scan递增方向","41. 磁道调度：FCFS \u002F SSTF \u002F SCAN（递增方向）",[26,13037,13038],{},"若干个等待访问磁盘者依次要访问的磁道为 20，44，40，4，80，12，76，假设每移动一个磁道需要 3 毫秒时间，移动臂当前位于 40 号柱面，请按下列算法分别写出访问序列并计算为完成上述各次访问总共花费的寻道时间。",[30,13040,13041,13044,13047],{},[33,13042,13043],{},"（1）先来先服务算法；",[33,13045,13046],{},"（2）最短寻道时间优先算法；",[33,13048,13049],{},"（3）扫描算法（当前磁头移动的方向为磁道递增）。",[26,13051,41],{},[26,13053,44],{},[13,13055,13057],{"id":13056},"_42-文件目录检索目录项分解的平均磁盘访问次数","42. 文件目录检索：目录项分解的平均磁盘访问次数",[26,13059,13060],{},"在实现文件系统时，一般为加快文件目录的检索速度，可利用\"文件控制块部分装入\"的方法。假设目录文件（即文件控制块）存放在磁盘上，磁盘的每个盘块为 512B，每个目录项占 128B，其中文件名占 11B。为提高检索速度，通常将目录项分解成两部分，第一部分（包括文件名和文件内部号）占 16B，第二部分（包括文件内部号和文件其他描述信息）占 122B。假设某一目录共有 254 个目录项（文件控制块），试分别给出前、后二种方法查找该目录文件某一目录项的平均访问磁盘次数。",[26,13062,41],{},[26,13064,44],{},[13,13066,13068],{"id":13067},"_43-磁鼓优化存储20个区1ms读取2ms处理","43. 磁鼓优化存储：20个区，1ms读取，2ms处理",[26,13070,13071],{},"旋转型设备上信息的优化分布能减少为若干个 I\u002FO 服务的总时间。设磁鼓上分为 20 个区，每区存放一个记录，磁鼓旋转一周需 20 毫秒，读出每个记录平均需用 1 毫秒，读出后经 2 毫秒处理，再继续处理下一个记录。在不知当前磁鼓位置的情况下：",[30,13073,13074,13077],{},[33,13075,13076],{},"（1）顺序存放记录 1、……，记录 20 时，试计算读出并处理 20 个记录的总时间；",[33,13078,13079],{},"（2）给出优先分布 20 个记录的一种方案，使得所花的总处理时间减少，且计算出这个方案所花的总时间。",[26,13081,41],{},[26,13083,44],{},[13,13085,13087],{"id":13086},"_44-分时操作系统设计重要进程与-io-瓶颈","44. 分时操作系统设计：重要进程与 I\u002FO 瓶颈",[26,13089,13090],{},"假设你需要为某企业设计一个分时操作系统，请回答以下问题：",[30,13092,13093,13096],{},[33,13094,13095],{},"(1) 你认为哪些系统进程最重要？",[33,13097,13098],{},"(2) 如果该操作系统主要负责处理 IO-Bounded 进程，你认为系统性能的瓶颈可能是什么？如何解决？",[26,13100,41],{},[26,13102,44],{},[13,13104,13106],{"id":13105},"_45-银行家算法单类资源s类-150个","45. 银行家算法：单类资源（S类 150个）",[26,13108,13109],{},"系统中具有 S 类资源 150 个，在 T0 时刻按下表所示分配给 3 个进程：",[53,13111,13112,13124],{},[56,13113,13114],{},[59,13115,13116,13118,13121],{},[62,13117,65],{"align":64},[62,13119,13120],{"align":64},"Maximum demand",[62,13122,13123],{"align":64},"Current allocation",[73,13125,13126,13135,13143],{},[59,13127,13128,13130,13133],{},[78,13129,80],{"align":64},[78,13131,13132],{"align":64},"70",[78,13134,7470],{"align":64},[59,13136,13137,13139,13141],{},[78,13138,90],{"align":64},[78,13140,3352],{"align":64},[78,13142,1703],{"align":64},[59,13144,13145,13147,13149],{},[78,13146,101],{"align":64},[78,13148,3352],{"align":64},[78,13150,13151],{"align":64},"45",[26,13153,13154],{},"对下列请求应用银行家算法逐步分别分析判定是否安全，如果是安全的，请给出一个可能的进程安全执行序列；如果不是安全的，请说明原因。",[30,13156,13157,13160],{},[33,13158,13159],{},"(1) 第 4 个进程 P4 到达，对资源 S 的最大需求为 60 个，当前请求分配 25 个；",[33,13161,13162],{},"(2) 第 4 个进程 P4 到达，对资源 S 的最大需求 50 个，当前请求分配 35 个。",[26,13164,41],{},[26,13166,44],{},[13,13168,13170],{"id":13169},"_46-请求分页快表地址转换过程与虚地址计算","46. 请求分页：快表地址转换过程与虚地址计算",[26,13172,13173],{},"设正在处理器上执行的一个进程的页表如下表所示，表中的虚页号和物理块号是十进制数，起始页号（块号）均为 0。所有的地址均是存储器字节地址。页的大小为 1024 字节。",[53,13175,13176,13195],{},[56,13177,13178],{},[59,13179,13180,13183,13186,13189,13192],{},[62,13181,13182],{"align":64},"虚页号",[62,13184,13185],{"align":64},"状态位",[62,13187,13188],{"align":64},"访问位",[62,13190,13191],{"align":64},"修改位",[62,13193,13194],{"align":64},"物理块号",[73,13196,13197,13210,13222,13235,13247,13259],{},[59,13198,13199,13202,13204,13206,13208],{},[78,13200,13201],{"align":64},"0",[78,13203,249],{"align":64},[78,13205,249],{"align":64},[78,13207,13201],{"align":64},[78,13209,306],{"align":64},[59,13211,13212,13214,13216,13218,13220],{},[78,13213,249],{"align":64},[78,13215,249],{"align":64},[78,13217,249],{"align":64},[78,13219,249],{"align":64},[78,13221,4050],{"align":64},[59,13223,13224,13226,13228,13230,13232],{},[78,13225,268],{"align":64},[78,13227,13201],{"align":64},[78,13229,13201],{"align":64},[78,13231,13201],{"align":64},[78,13233,13234],{"align":64},"-",[59,13236,13237,13239,13241,13243,13245],{},[78,13238,287],{"align":64},[78,13240,249],{"align":64},[78,13242,13201],{"align":64},[78,13244,13201],{"align":64},[78,13246,268],{"align":64},[59,13248,13249,13251,13253,13255,13257],{},[78,13250,306],{"align":64},[78,13252,13201],{"align":64},[78,13254,13201],{"align":64},[78,13256,13201],{"align":64},[78,13258,13234],{"align":64},[59,13260,13261,13263,13265,13267,13269],{},[78,13262,324],{"align":64},[78,13264,249],{"align":64},[78,13266,13201],{"align":64},[78,13268,249],{"align":64},[78,13270,13201],{"align":64},[26,13272,13273],{},"注：当某页被访问时，其访问位置 1。",[30,13275,13276,13279],{},[33,13277,13278],{},"(1) 详述在设有快表的请求分页存储管理系统中，一个虚地址转换成物理内存地址的过程。",[33,13280,13281],{},"(2) 下列十进制虚地址对应于什么物理地址：5579，2232",[26,13283,41],{},[26,13285,44],{},[13,13287,13289],{"id":13288},"_47题目缺失","47.（题目缺失）",[26,13291,41],{},[26,13293,44],{},[13,13295,13297],{"id":13296},"_48-sstf-与-scan-磁道调度200个柱面","48. SSTF 与 SCAN 磁道调度（200个柱面）",[26,13299,13300],{},"假定一个磁盘有 200 个柱面（编号 0-199），磁盘请求队列由对如下柱面的请求序列构成：50, 60, 30, 18, 90, 165, 150, 38, 12, 190. 已知磁头当前位于 95 号柱面，移动方向为向内。",[30,13302,13303,13306],{},[33,13304,13305],{},"(1) 如果系统采用 SSTF 算法进行调度，那么系统处理完上述所有的磁盘请求所需的寻道距离是多少？",[33,13307,13308],{},"(2) 如果系统采用 SCAN 算法进行调度，那么系统处理完上述所有的磁盘请求所需的寻道距离是多少？",[26,13310,41],{},[26,13312,44],{},[13,13314,13316],{"id":13315},"_49-请求分页地址位数与物理块数计算","49. 请求分页：地址位数与物理块数计算",[26,13318,13319],{},"一个采用请求式存储管理的计算机系统，其主存（实存）容量为 256M 字节，虚存容量（给用户的最大地址空间）为 4G 字节，页面大小为 4K 字节，试问：",[30,13321,13322,13325,13328,13331,13334],{},[33,13323,13324],{},"(1) 主存物理地址应设为多少位？",[33,13326,13327],{},"(2) 主存中有多少物理块？",[33,13329,13330],{},"(3) 虚拟地址应该设多少位？",[33,13332,13333],{},"(4) 虚拟地址空间最多可以有多少页？",[33,13335,13336],{},"(5) 页内最大和最小偏移量是多少？",[26,13338,41],{},[26,13340,44],{},[13,13342,13344],{"id":13343},"_50-页面置换算法计算fifo-lru-opt","50. 页面置换算法计算（FIFO \u002F LRU \u002F OPT）",[26,13346,13347],{},"设某作业占有 7 个页面，如果在主存中只允许装入 4 个工作页面（即工作集为 4），作业运行时，实际访问页面的顺序是：1, 2, 3, 6, 4, 7, 3, 2, 1, 4, 7, 5, 6, 5, 2, 1。试用 FIFO、LRU 和 OPT 页面置换算法，列出各自的页面淘汰顺序和页面置换次数。",[26,13349,41],{},[554,13351,9524],{"id":13352},"概念核对-concept-check-1",[30,13354,13355,13361,13370],{},[33,13356,13357,13360],{},[563,13358,13359],{},"工作集大小："," 题目规定只允许装入 4 个工作页面，意味着内存中最多只有 4 个物理块（Frame）供该作业使用。",[33,13362,13363,13366,13367,701],{},[563,13364,13365],{},"缺页中断 (Page Fault) 与 页面置换 (Page Replacement) 的区别："," 当内存块未满时，调入新页面只会发生\"缺页中断\"，但不会发生\"页面置换\"（因为有空闲位置）。只有当 4 个块都装满后，再调入新页面才会发生\"置换\"。题目明确要求计算的是",[563,13368,13369],{},"置换次数",[33,13371,13372,13375],{},[563,13373,13374],{},"三大算法：",[30,13376,13377,13380,13383],{},[33,13378,13379],{},"FIFO (先进先出)：淘汰在内存中驻留时间最长的页面。",[33,13381,13382],{},"LRU (最近最久未使用)：淘汰在最近一段时间内最久没有被访问过的页面（向前看）。",[33,13384,13385],{},"OPT (最佳置换)：淘汰在未来最长时间内不再被访问的页面（向后看，理想算法）。",[554,13387,13388],{"id":13388},"原理解析与计算过程",[26,13390,13391,13392,701],{},"给定的访问序列长度为16：1, 2, 3, 6, 4, 7, 3, 2, 1, 4, 7, 5, 6, 5, 2, 1。\n初始 4 个空闲块，装入 1, 2, 3, 6 时发生 4 次缺页，0 次置换。此时内存为 ",[568,13393,13395,13427],{"className":13394},[571],[568,13396,13398],{"className":13397},[575],[577,13399,13400],{"xmlns":579},[581,13401,13402,13424],{},[584,13403,13404,13407,13409,13411,13413,13415,13417,13419,13421],{},[591,13405,13406],{"stretchy":1061},"⟨",[595,13408,249],{},[591,13410,6777],{"separator":628},[595,13412,268],{},[591,13414,6777],{"separator":628},[595,13416,287],{},[591,13418,6777],{"separator":628},[595,13420,343],{},[591,13422,13423],{"stretchy":1061},"⟩",[620,13425,13426],{"encoding":622},"\\langle1, 2, 3, 6\\rangle",[568,13428,13430],{"className":13429,"ariaHidden":628},[627],[568,13431,13433,13436,13439,13442,13445,13448,13451,13454,13457,13460,13463,13466,13469],{"className":13432},[632],[568,13434],{"className":13435,"style":662},[636],[568,13437,13406],{"className":13438},[872],[568,13440,249],{"className":13441},[641],[568,13443,6777],{"className":13444},[6809],[568,13446],{"className":13447,"style":6813},[647],[568,13449,268],{"className":13450},[641],[568,13452,6777],{"className":13453},[6809],[568,13455],{"className":13456,"style":6813},[647],[568,13458,287],{"className":13459},[641],[568,13461,6777],{"className":13462},[6809],[568,13464],{"className":13465,"style":6813},[647],[568,13467,343],{"className":13468},[641],[568,13470,13423],{"className":13471},[955],[13473,13474,13476],"h4",{"id":13475},"_1-fifo-先进先出","1. FIFO (先进先出)",[30,13478,13479,13566,13652,13657,13743,13829,13835,13921,14007,14012],{},[33,13480,13481,13483,13484,13487,13488,701],{},[563,13482,306],{},"：内存满，最先进入的是 1。",[563,13485,13486],{},"淘汰 1","。内存变为 ",[568,13489,13491,13521],{"className":13490},[571],[568,13492,13494],{"className":13493},[575],[577,13495,13496],{"xmlns":579},[581,13497,13498,13518],{},[584,13499,13500,13502,13504,13506,13508,13510,13512,13514,13516],{},[591,13501,13406],{"stretchy":1061},[595,13503,268],{},[591,13505,6777],{"separator":628},[595,13507,287],{},[591,13509,6777],{"separator":628},[595,13511,343],{},[591,13513,6777],{"separator":628},[595,13515,306],{},[591,13517,13423],{"stretchy":1061},[620,13519,13520],{"encoding":622},"\\langle2, 3, 6, 4\\rangle",[568,13522,13524],{"className":13523,"ariaHidden":628},[627],[568,13525,13527,13530,13533,13536,13539,13542,13545,13548,13551,13554,13557,13560,13563],{"className":13526},[632],[568,13528],{"className":13529,"style":662},[636],[568,13531,13406],{"className":13532},[872],[568,13534,268],{"className":13535},[641],[568,13537,6777],{"className":13538},[6809],[568,13540],{"className":13541,"style":6813},[647],[568,13543,287],{"className":13544},[641],[568,13546,6777],{"className":13547},[6809],[568,13549],{"className":13550,"style":6813},[647],[568,13552,343],{"className":13553},[641],[568,13555,6777],{"className":13556},[6809],[568,13558],{"className":13559,"style":6813},[647],[568,13561,306],{"className":13562},[641],[568,13564,13423],{"className":13565},[955],[33,13567,13568,13570,13571,13487,13574,701],{},[563,13569,4050],{},"：最早进入的是 2。",[563,13572,13573],{},"淘汰 2",[568,13575,13577,13607],{"className":13576},[571],[568,13578,13580],{"className":13579},[575],[577,13581,13582],{"xmlns":579},[581,13583,13584,13604],{},[584,13585,13586,13588,13590,13592,13594,13596,13598,13600,13602],{},[591,13587,13406],{"stretchy":1061},[595,13589,287],{},[591,13591,6777],{"separator":628},[595,13593,343],{},[591,13595,6777],{"separator":628},[595,13597,306],{},[591,13599,6777],{"separator":628},[595,13601,4050],{},[591,13603,13423],{"stretchy":1061},[620,13605,13606],{"encoding":622},"\\langle3, 6, 4, 7\\rangle",[568,13608,13610],{"className":13609,"ariaHidden":628},[627],[568,13611,13613,13616,13619,13622,13625,13628,13631,13634,13637,13640,13643,13646,13649],{"className":13612},[632],[568,13614],{"className":13615,"style":662},[636],[568,13617,13406],{"className":13618},[872],[568,13620,287],{"className":13621},[641],[568,13623,6777],{"className":13624},[6809],[568,13626],{"className":13627,"style":6813},[647],[568,13629,343],{"className":13630},[641],[568,13632,6777],{"className":13633},[6809],[568,13635],{"className":13636,"style":6813},[647],[568,13638,306],{"className":13639},[641],[568,13641,6777],{"className":13642},[6809],[568,13644],{"className":13645,"style":6813},[647],[568,13647,4050],{"className":13648},[641],[568,13650,13423],{"className":13651},[955],[33,13653,13654,13656],{},[563,13655,287],{},"：命中。",[33,13658,13659,13661,13662,13487,13665,701],{},[563,13660,268],{},"：最早进入的是 3。",[563,13663,13664],{},"淘汰 3",[568,13666,13668,13698],{"className":13667},[571],[568,13669,13671],{"className":13670},[575],[577,13672,13673],{"xmlns":579},[581,13674,13675,13695],{},[584,13676,13677,13679,13681,13683,13685,13687,13689,13691,13693],{},[591,13678,13406],{"stretchy":1061},[595,13680,343],{},[591,13682,6777],{"separator":628},[595,13684,306],{},[591,13686,6777],{"separator":628},[595,13688,4050],{},[591,13690,6777],{"separator":628},[595,13692,268],{},[591,13694,13423],{"stretchy":1061},[620,13696,13697],{"encoding":622},"\\langle6, 4, 7, 2\\rangle",[568,13699,13701],{"className":13700,"ariaHidden":628},[627],[568,13702,13704,13707,13710,13713,13716,13719,13722,13725,13728,13731,13734,13737,13740],{"className":13703},[632],[568,13705],{"className":13706,"style":662},[636],[568,13708,13406],{"className":13709},[872],[568,13711,343],{"className":13712},[641],[568,13714,6777],{"className":13715},[6809],[568,13717],{"className":13718,"style":6813},[647],[568,13720,306],{"className":13721},[641],[568,13723,6777],{"className":13724},[6809],[568,13726],{"className":13727,"style":6813},[647],[568,13729,4050],{"className":13730},[641],[568,13732,6777],{"className":13733},[6809],[568,13735],{"className":13736,"style":6813},[647],[568,13738,268],{"className":13739},[641],[568,13741,13423],{"className":13742},[955],[33,13744,13745,13747,13748,13487,13751,701],{},[563,13746,249],{},"：最早进入的是 6。",[563,13749,13750],{},"淘汰 6",[568,13752,13754,13784],{"className":13753},[571],[568,13755,13757],{"className":13756},[575],[577,13758,13759],{"xmlns":579},[581,13760,13761,13781],{},[584,13762,13763,13765,13767,13769,13771,13773,13775,13777,13779],{},[591,13764,13406],{"stretchy":1061},[595,13766,306],{},[591,13768,6777],{"separator":628},[595,13770,4050],{},[591,13772,6777],{"separator":628},[595,13774,268],{},[591,13776,6777],{"separator":628},[595,13778,249],{},[591,13780,13423],{"stretchy":1061},[620,13782,13783],{"encoding":622},"\\langle4, 7, 2, 1\\rangle",[568,13785,13787],{"className":13786,"ariaHidden":628},[627],[568,13788,13790,13793,13796,13799,13802,13805,13808,13811,13814,13817,13820,13823,13826],{"className":13789},[632],[568,13791],{"className":13792,"style":662},[636],[568,13794,13406],{"className":13795},[872],[568,13797,306],{"className":13798},[641],[568,13800,6777],{"className":13801},[6809],[568,13803],{"className":13804,"style":6813},[647],[568,13806,4050],{"className":13807},[641],[568,13809,6777],{"className":13810},[6809],[568,13812],{"className":13813,"style":6813},[647],[568,13815,268],{"className":13816},[641],[568,13818,6777],{"className":13819},[6809],[568,13821],{"className":13822,"style":6813},[647],[568,13824,249],{"className":13825},[641],[568,13827,13423],{"className":13828},[955],[33,13830,13831,13834],{},[563,13832,13833],{},"4, 7","：连续命中。",[33,13836,13837,13839,13840,13487,13843,701],{},[563,13838,324],{},"：最早进入的是 4。",[563,13841,13842],{},"淘汰 4",[568,13844,13846,13876],{"className":13845},[571],[568,13847,13849],{"className":13848},[575],[577,13850,13851],{"xmlns":579},[581,13852,13853,13873],{},[584,13854,13855,13857,13859,13861,13863,13865,13867,13869,13871],{},[591,13856,13406],{"stretchy":1061},[595,13858,4050],{},[591,13860,6777],{"separator":628},[595,13862,268],{},[591,13864,6777],{"separator":628},[595,13866,249],{},[591,13868,6777],{"separator":628},[595,13870,324],{},[591,13872,13423],{"stretchy":1061},[620,13874,13875],{"encoding":622},"\\langle7, 2, 1, 5\\rangle",[568,13877,13879],{"className":13878,"ariaHidden":628},[627],[568,13880,13882,13885,13888,13891,13894,13897,13900,13903,13906,13909,13912,13915,13918],{"className":13881},[632],[568,13883],{"className":13884,"style":662},[636],[568,13886,13406],{"className":13887},[872],[568,13889,4050],{"className":13890},[641],[568,13892,6777],{"className":13893},[6809],[568,13895],{"className":13896,"style":6813},[647],[568,13898,268],{"className":13899},[641],[568,13901,6777],{"className":13902},[6809],[568,13904],{"className":13905,"style":6813},[647],[568,13907,249],{"className":13908},[641],[568,13910,6777],{"className":13911},[6809],[568,13913],{"className":13914,"style":6813},[647],[568,13916,324],{"className":13917},[641],[568,13919,13423],{"className":13920},[955],[33,13922,13923,13925,13926,13487,13929,701],{},[563,13924,343],{},"：最早进入的是 7。",[563,13927,13928],{},"淘汰 7",[568,13930,13932,13962],{"className":13931},[571],[568,13933,13935],{"className":13934},[575],[577,13936,13937],{"xmlns":579},[581,13938,13939,13959],{},[584,13940,13941,13943,13945,13947,13949,13951,13953,13955,13957],{},[591,13942,13406],{"stretchy":1061},[595,13944,268],{},[591,13946,6777],{"separator":628},[595,13948,249],{},[591,13950,6777],{"separator":628},[595,13952,324],{},[591,13954,6777],{"separator":628},[595,13956,343],{},[591,13958,13423],{"stretchy":1061},[620,13960,13961],{"encoding":622},"\\langle2, 1, 5, 6\\rangle",[568,13963,13965],{"className":13964,"ariaHidden":628},[627],[568,13966,13968,13971,13974,13977,13980,13983,13986,13989,13992,13995,13998,14001,14004],{"className":13967},[632],[568,13969],{"className":13970,"style":662},[636],[568,13972,13406],{"className":13973},[872],[568,13975,268],{"className":13976},[641],[568,13978,6777],{"className":13979},[6809],[568,13981],{"className":13982,"style":6813},[647],[568,13984,249],{"className":13985},[641],[568,13987,6777],{"className":13988},[6809],[568,13990],{"className":13991,"style":6813},[647],[568,13993,324],{"className":13994},[641],[568,13996,6777],{"className":13997},[6809],[568,13999],{"className":14000,"style":6813},[647],[568,14002,343],{"className":14003},[641],[568,14005,13423],{"className":14006},[955],[33,14008,14009,13834],{},[563,14010,14011],{},"5, 2, 1",[33,14013,14014,14017],{},[563,14015,14016],{},"结果：",[30,14018,14019,14025],{},[33,14020,14021,14024],{},[563,14022,14023],{},"淘汰顺序："," 1, 2, 3, 6, 4, 7",[33,14026,14027,14030],{},[563,14028,14029],{},"置换次数："," 6 次（总缺页10次）",[13473,14032,14034],{"id":14033},"_2-lru-最近最久未使用","2. LRU (最近最久未使用)",[26,14036,14037,14038,14115],{},"初始装入后为 ",[568,14039,14041,14070],{"className":14040},[571],[568,14042,14044],{"className":14043},[575],[577,14045,14046],{"xmlns":579},[581,14047,14048,14068],{},[584,14049,14050,14052,14054,14056,14058,14060,14062,14064,14066],{},[591,14051,13406],{"stretchy":1061},[595,14053,249],{},[591,14055,6777],{"separator":628},[595,14057,268],{},[591,14059,6777],{"separator":628},[595,14061,287],{},[591,14063,6777],{"separator":628},[595,14065,343],{},[591,14067,13423],{"stretchy":1061},[620,14069,13426],{"encoding":622},[568,14071,14073],{"className":14072,"ariaHidden":628},[627],[568,14074,14076,14079,14082,14085,14088,14091,14094,14097,14100,14103,14106,14109,14112],{"className":14075},[632],[568,14077],{"className":14078,"style":662},[636],[568,14080,13406],{"className":14081},[872],[568,14083,249],{"className":14084},[641],[568,14086,6777],{"className":14087},[6809],[568,14089],{"className":14090,"style":6813},[647],[568,14092,268],{"className":14093},[641],[568,14095,6777],{"className":14096},[6809],[568,14098],{"className":14099,"style":6813},[647],[568,14101,287],{"className":14102},[641],[568,14104,6777],{"className":14105},[6809],[568,14107],{"className":14108,"style":6813},[647],[568,14110,343],{"className":14111},[641],[568,14113,13423],{"className":14114},[955],"（右侧为最新使用）。",[30,14117,14118,14203,14287,14370,14455,14540,14625,14710,14794,14878,14961,15045,15129],{},[33,14119,14120,14122,14123,14125,14126,701],{},[563,14121,306],{},"：最久未用是 1。",[563,14124,13486],{},"。变为 ",[568,14127,14129,14158],{"className":14128},[571],[568,14130,14132],{"className":14131},[575],[577,14133,14134],{"xmlns":579},[581,14135,14136,14156],{},[584,14137,14138,14140,14142,14144,14146,14148,14150,14152,14154],{},[591,14139,13406],{"stretchy":1061},[595,14141,268],{},[591,14143,6777],{"separator":628},[595,14145,287],{},[591,14147,6777],{"separator":628},[595,14149,343],{},[591,14151,6777],{"separator":628},[595,14153,306],{},[591,14155,13423],{"stretchy":1061},[620,14157,13520],{"encoding":622},[568,14159,14161],{"className":14160,"ariaHidden":628},[627],[568,14162,14164,14167,14170,14173,14176,14179,14182,14185,14188,14191,14194,14197,14200],{"className":14163},[632],[568,14165],{"className":14166,"style":662},[636],[568,14168,13406],{"className":14169},[872],[568,14171,268],{"className":14172},[641],[568,14174,6777],{"className":14175},[6809],[568,14177],{"className":14178,"style":6813},[647],[568,14180,287],{"className":14181},[641],[568,14183,6777],{"className":14184},[6809],[568,14186],{"className":14187,"style":6813},[647],[568,14189,343],{"className":14190},[641],[568,14192,6777],{"className":14193},[6809],[568,14195],{"className":14196,"style":6813},[647],[568,14198,306],{"className":14199},[641],[568,14201,13423],{"className":14202},[955],[33,14204,14205,14207,14208,14125,14210,701],{},[563,14206,4050],{},"：最久未用是 2。",[563,14209,13573],{},[568,14211,14213,14242],{"className":14212},[571],[568,14214,14216],{"className":14215},[575],[577,14217,14218],{"xmlns":579},[581,14219,14220,14240],{},[584,14221,14222,14224,14226,14228,14230,14232,14234,14236,14238],{},[591,14223,13406],{"stretchy":1061},[595,14225,287],{},[591,14227,6777],{"separator":628},[595,14229,343],{},[591,14231,6777],{"separator":628},[595,14233,306],{},[591,14235,6777],{"separator":628},[595,14237,4050],{},[591,14239,13423],{"stretchy":1061},[620,14241,13606],{"encoding":622},[568,14243,14245],{"className":14244,"ariaHidden":628},[627],[568,14246,14248,14251,14254,14257,14260,14263,14266,14269,14272,14275,14278,14281,14284],{"className":14247},[632],[568,14249],{"className":14250,"style":662},[636],[568,14252,13406],{"className":14253},[872],[568,14255,287],{"className":14256},[641],[568,14258,6777],{"className":14259},[6809],[568,14261],{"className":14262,"style":6813},[647],[568,14264,343],{"className":14265},[641],[568,14267,6777],{"className":14268},[6809],[568,14270],{"className":14271,"style":6813},[647],[568,14273,306],{"className":14274},[641],[568,14276,6777],{"className":14277},[6809],[568,14279],{"className":14280,"style":6813},[647],[568,14282,4050],{"className":14283},[641],[568,14285,13423],{"className":14286},[955],[33,14288,14289,14291,14292,701],{},[563,14290,287],{},"：命中。更新顺序变为 ",[568,14293,14295,14325],{"className":14294},[571],[568,14296,14298],{"className":14297},[575],[577,14299,14300],{"xmlns":579},[581,14301,14302,14322],{},[584,14303,14304,14306,14308,14310,14312,14314,14316,14318,14320],{},[591,14305,13406],{"stretchy":1061},[595,14307,343],{},[591,14309,6777],{"separator":628},[595,14311,306],{},[591,14313,6777],{"separator":628},[595,14315,4050],{},[591,14317,6777],{"separator":628},[595,14319,287],{},[591,14321,13423],{"stretchy":1061},[620,14323,14324],{"encoding":622},"\\langle6, 4, 7, 3\\rangle",[568,14326,14328],{"className":14327,"ariaHidden":628},[627],[568,14329,14331,14334,14337,14340,14343,14346,14349,14352,14355,14358,14361,14364,14367],{"className":14330},[632],[568,14332],{"className":14333,"style":662},[636],[568,14335,13406],{"className":14336},[872],[568,14338,343],{"className":14339},[641],[568,14341,6777],{"className":14342},[6809],[568,14344],{"className":14345,"style":6813},[647],[568,14347,306],{"className":14348},[641],[568,14350,6777],{"className":14351},[6809],[568,14353],{"className":14354,"style":6813},[647],[568,14356,4050],{"className":14357},[641],[568,14359,6777],{"className":14360},[6809],[568,14362],{"className":14363,"style":6813},[647],[568,14365,287],{"className":14366},[641],[568,14368,13423],{"className":14369},[955],[33,14371,14372,14374,14375,14125,14377,701],{},[563,14373,268],{},"：最久未用是 6。",[563,14376,13750],{},[568,14378,14380,14410],{"className":14379},[571],[568,14381,14383],{"className":14382},[575],[577,14384,14385],{"xmlns":579},[581,14386,14387,14407],{},[584,14388,14389,14391,14393,14395,14397,14399,14401,14403,14405],{},[591,14390,13406],{"stretchy":1061},[595,14392,306],{},[591,14394,6777],{"separator":628},[595,14396,4050],{},[591,14398,6777],{"separator":628},[595,14400,287],{},[591,14402,6777],{"separator":628},[595,14404,268],{},[591,14406,13423],{"stretchy":1061},[620,14408,14409],{"encoding":622},"\\langle4, 7, 3, 2\\rangle",[568,14411,14413],{"className":14412,"ariaHidden":628},[627],[568,14414,14416,14419,14422,14425,14428,14431,14434,14437,14440,14443,14446,14449,14452],{"className":14415},[632],[568,14417],{"className":14418,"style":662},[636],[568,14420,13406],{"className":14421},[872],[568,14423,306],{"className":14424},[641],[568,14426,6777],{"className":14427},[6809],[568,14429],{"className":14430,"style":6813},[647],[568,14432,4050],{"className":14433},[641],[568,14435,6777],{"className":14436},[6809],[568,14438],{"className":14439,"style":6813},[647],[568,14441,287],{"className":14442},[641],[568,14444,6777],{"className":14445},[6809],[568,14447],{"className":14448,"style":6813},[647],[568,14450,268],{"className":14451},[641],[568,14453,13423],{"className":14454},[955],[33,14456,14457,14459,14460,14125,14462,701],{},[563,14458,249],{},"：最久未用是 4。",[563,14461,13842],{},[568,14463,14465,14495],{"className":14464},[571],[568,14466,14468],{"className":14467},[575],[577,14469,14470],{"xmlns":579},[581,14471,14472,14492],{},[584,14473,14474,14476,14478,14480,14482,14484,14486,14488,14490],{},[591,14475,13406],{"stretchy":1061},[595,14477,4050],{},[591,14479,6777],{"separator":628},[595,14481,287],{},[591,14483,6777],{"separator":628},[595,14485,268],{},[591,14487,6777],{"separator":628},[595,14489,249],{},[591,14491,13423],{"stretchy":1061},[620,14493,14494],{"encoding":622},"\\langle7, 3, 2, 1\\rangle",[568,14496,14498],{"className":14497,"ariaHidden":628},[627],[568,14499,14501,14504,14507,14510,14513,14516,14519,14522,14525,14528,14531,14534,14537],{"className":14500},[632],[568,14502],{"className":14503,"style":662},[636],[568,14505,13406],{"className":14506},[872],[568,14508,4050],{"className":14509},[641],[568,14511,6777],{"className":14512},[6809],[568,14514],{"className":14515,"style":6813},[647],[568,14517,287],{"className":14518},[641],[568,14520,6777],{"className":14521},[6809],[568,14523],{"className":14524,"style":6813},[647],[568,14526,268],{"className":14527},[641],[568,14529,6777],{"className":14530},[6809],[568,14532],{"className":14533,"style":6813},[647],[568,14535,249],{"className":14536},[641],[568,14538,13423],{"className":14539},[955],[33,14541,14542,14544,14545,14125,14547,701],{},[563,14543,306],{},"：最久未用是 7。",[563,14546,13928],{},[568,14548,14550,14580],{"className":14549},[571],[568,14551,14553],{"className":14552},[575],[577,14554,14555],{"xmlns":579},[581,14556,14557,14577],{},[584,14558,14559,14561,14563,14565,14567,14569,14571,14573,14575],{},[591,14560,13406],{"stretchy":1061},[595,14562,287],{},[591,14564,6777],{"separator":628},[595,14566,268],{},[591,14568,6777],{"separator":628},[595,14570,249],{},[591,14572,6777],{"separator":628},[595,14574,306],{},[591,14576,13423],{"stretchy":1061},[620,14578,14579],{"encoding":622},"\\langle3, 2, 1, 4\\rangle",[568,14581,14583],{"className":14582,"ariaHidden":628},[627],[568,14584,14586,14589,14592,14595,14598,14601,14604,14607,14610,14613,14616,14619,14622],{"className":14585},[632],[568,14587],{"className":14588,"style":662},[636],[568,14590,13406],{"className":14591},[872],[568,14593,287],{"className":14594},[641],[568,14596,6777],{"className":14597},[6809],[568,14599],{"className":14600,"style":6813},[647],[568,14602,268],{"className":14603},[641],[568,14605,6777],{"className":14606},[6809],[568,14608],{"className":14609,"style":6813},[647],[568,14611,249],{"className":14612},[641],[568,14614,6777],{"className":14615},[6809],[568,14617],{"className":14618,"style":6813},[647],[568,14620,306],{"className":14621},[641],[568,14623,13423],{"className":14624},[955],[33,14626,14627,14629,14630,14125,14632,701],{},[563,14628,4050],{},"：最久未用是 3。",[563,14631,13664],{},[568,14633,14635,14665],{"className":14634},[571],[568,14636,14638],{"className":14637},[575],[577,14639,14640],{"xmlns":579},[581,14641,14642,14662],{},[584,14643,14644,14646,14648,14650,14652,14654,14656,14658,14660],{},[591,14645,13406],{"stretchy":1061},[595,14647,268],{},[591,14649,6777],{"separator":628},[595,14651,249],{},[591,14653,6777],{"separator":628},[595,14655,306],{},[591,14657,6777],{"separator":628},[595,14659,4050],{},[591,14661,13423],{"stretchy":1061},[620,14663,14664],{"encoding":622},"\\langle2, 1, 4, 7\\rangle",[568,14666,14668],{"className":14667,"ariaHidden":628},[627],[568,14669,14671,14674,14677,14680,14683,14686,14689,14692,14695,14698,14701,14704,14707],{"className":14670},[632],[568,14672],{"className":14673,"style":662},[636],[568,14675,13406],{"className":14676},[872],[568,14678,268],{"className":14679},[641],[568,14681,6777],{"className":14682},[6809],[568,14684],{"className":14685,"style":6813},[647],[568,14687,249],{"className":14688},[641],[568,14690,6777],{"className":14691},[6809],[568,14693],{"className":14694,"style":6813},[647],[568,14696,306],{"className":14697},[641],[568,14699,6777],{"className":14700},[6809],[568,14702],{"className":14703,"style":6813},[647],[568,14705,4050],{"className":14706},[641],[568,14708,13423],{"className":14709},[955],[33,14711,14712,14207,14714,14125,14716,701],{},[563,14713,324],{},[563,14715,13573],{},[568,14717,14719,14749],{"className":14718},[571],[568,14720,14722],{"className":14721},[575],[577,14723,14724],{"xmlns":579},[581,14725,14726,14746],{},[584,14727,14728,14730,14732,14734,14736,14738,14740,14742,14744],{},[591,14729,13406],{"stretchy":1061},[595,14731,249],{},[591,14733,6777],{"separator":628},[595,14735,306],{},[591,14737,6777],{"separator":628},[595,14739,4050],{},[591,14741,6777],{"separator":628},[595,14743,324],{},[591,14745,13423],{"stretchy":1061},[620,14747,14748],{"encoding":622},"\\langle1, 4, 7, 5\\rangle",[568,14750,14752],{"className":14751,"ariaHidden":628},[627],[568,14753,14755,14758,14761,14764,14767,14770,14773,14776,14779,14782,14785,14788,14791],{"className":14754},[632],[568,14756],{"className":14757,"style":662},[636],[568,14759,13406],{"className":14760},[872],[568,14762,249],{"className":14763},[641],[568,14765,6777],{"className":14766},[6809],[568,14768],{"className":14769,"style":6813},[647],[568,14771,306],{"className":14772},[641],[568,14774,6777],{"className":14775},[6809],[568,14777],{"className":14778,"style":6813},[647],[568,14780,4050],{"className":14781},[641],[568,14783,6777],{"className":14784},[6809],[568,14786],{"className":14787,"style":6813},[647],[568,14789,324],{"className":14790},[641],[568,14792,13423],{"className":14793},[955],[33,14795,14796,14122,14798,14125,14800,701],{},[563,14797,343],{},[563,14799,13486],{},[568,14801,14803,14833],{"className":14802},[571],[568,14804,14806],{"className":14805},[575],[577,14807,14808],{"xmlns":579},[581,14809,14810,14830],{},[584,14811,14812,14814,14816,14818,14820,14822,14824,14826,14828],{},[591,14813,13406],{"stretchy":1061},[595,14815,306],{},[591,14817,6777],{"separator":628},[595,14819,4050],{},[591,14821,6777],{"separator":628},[595,14823,324],{},[591,14825,6777],{"separator":628},[595,14827,343],{},[591,14829,13423],{"stretchy":1061},[620,14831,14832],{"encoding":622},"\\langle4, 7, 5, 6\\rangle",[568,14834,14836],{"className":14835,"ariaHidden":628},[627],[568,14837,14839,14842,14845,14848,14851,14854,14857,14860,14863,14866,14869,14872,14875],{"className":14838},[632],[568,14840],{"className":14841,"style":662},[636],[568,14843,13406],{"className":14844},[872],[568,14846,306],{"className":14847},[641],[568,14849,6777],{"className":14850},[6809],[568,14852],{"className":14853,"style":6813},[647],[568,14855,4050],{"className":14856},[641],[568,14858,6777],{"className":14859},[6809],[568,14861],{"className":14862,"style":6813},[647],[568,14864,324],{"className":14865},[641],[568,14867,6777],{"className":14868},[6809],[568,14870],{"className":14871,"style":6813},[647],[568,14873,343],{"className":14874},[641],[568,14876,13423],{"className":14877},[955],[33,14879,14880,14882,14883,701],{},[563,14881,324],{},"：命中。变为 ",[568,14884,14886,14916],{"className":14885},[571],[568,14887,14889],{"className":14888},[575],[577,14890,14891],{"xmlns":579},[581,14892,14893,14913],{},[584,14894,14895,14897,14899,14901,14903,14905,14907,14909,14911],{},[591,14896,13406],{"stretchy":1061},[595,14898,306],{},[591,14900,6777],{"separator":628},[595,14902,4050],{},[591,14904,6777],{"separator":628},[595,14906,343],{},[591,14908,6777],{"separator":628},[595,14910,324],{},[591,14912,13423],{"stretchy":1061},[620,14914,14915],{"encoding":622},"\\langle4, 7, 6, 5\\rangle",[568,14917,14919],{"className":14918,"ariaHidden":628},[627],[568,14920,14922,14925,14928,14931,14934,14937,14940,14943,14946,14949,14952,14955,14958],{"className":14921},[632],[568,14923],{"className":14924,"style":662},[636],[568,14926,13406],{"className":14927},[872],[568,14929,306],{"className":14930},[641],[568,14932,6777],{"className":14933},[6809],[568,14935],{"className":14936,"style":6813},[647],[568,14938,4050],{"className":14939},[641],[568,14941,6777],{"className":14942},[6809],[568,14944],{"className":14945,"style":6813},[647],[568,14947,343],{"className":14948},[641],[568,14950,6777],{"className":14951},[6809],[568,14953],{"className":14954,"style":6813},[647],[568,14956,324],{"className":14957},[641],[568,14959,13423],{"className":14960},[955],[33,14962,14963,14459,14965,14125,14967,701],{},[563,14964,268],{},[563,14966,13842],{},[568,14968,14970,15000],{"className":14969},[571],[568,14971,14973],{"className":14972},[575],[577,14974,14975],{"xmlns":579},[581,14976,14977,14997],{},[584,14978,14979,14981,14983,14985,14987,14989,14991,14993,14995],{},[591,14980,13406],{"stretchy":1061},[595,14982,4050],{},[591,14984,6777],{"separator":628},[595,14986,343],{},[591,14988,6777],{"separator":628},[595,14990,324],{},[591,14992,6777],{"separator":628},[595,14994,268],{},[591,14996,13423],{"stretchy":1061},[620,14998,14999],{"encoding":622},"\\langle7, 6, 5, 2\\rangle",[568,15001,15003],{"className":15002,"ariaHidden":628},[627],[568,15004,15006,15009,15012,15015,15018,15021,15024,15027,15030,15033,15036,15039,15042],{"className":15005},[632],[568,15007],{"className":15008,"style":662},[636],[568,15010,13406],{"className":15011},[872],[568,15013,4050],{"className":15014},[641],[568,15016,6777],{"className":15017},[6809],[568,15019],{"className":15020,"style":6813},[647],[568,15022,343],{"className":15023},[641],[568,15025,6777],{"className":15026},[6809],[568,15028],{"className":15029,"style":6813},[647],[568,15031,324],{"className":15032},[641],[568,15034,6777],{"className":15035},[6809],[568,15037],{"className":15038,"style":6813},[647],[568,15040,268],{"className":15041},[641],[568,15043,13423],{"className":15044},[955],[33,15046,15047,14544,15049,14125,15051,701],{},[563,15048,249],{},[563,15050,13928],{},[568,15052,15054,15084],{"className":15053},[571],[568,15055,15057],{"className":15056},[575],[577,15058,15059],{"xmlns":579},[581,15060,15061,15081],{},[584,15062,15063,15065,15067,15069,15071,15073,15075,15077,15079],{},[591,15064,13406],{"stretchy":1061},[595,15066,343],{},[591,15068,6777],{"separator":628},[595,15070,324],{},[591,15072,6777],{"separator":628},[595,15074,268],{},[591,15076,6777],{"separator":628},[595,15078,249],{},[591,15080,13423],{"stretchy":1061},[620,15082,15083],{"encoding":622},"\\langle6, 5, 2, 1\\rangle",[568,15085,15087],{"className":15086,"ariaHidden":628},[627],[568,15088,15090,15093,15096,15099,15102,15105,15108,15111,15114,15117,15120,15123,15126],{"className":15089},[632],[568,15091],{"className":15092,"style":662},[636],[568,15094,13406],{"className":15095},[872],[568,15097,343],{"className":15098},[641],[568,15100,6777],{"className":15101},[6809],[568,15103],{"className":15104,"style":6813},[647],[568,15106,324],{"className":15107},[641],[568,15109,6777],{"className":15110},[6809],[568,15112],{"className":15113,"style":6813},[647],[568,15115,268],{"className":15116},[641],[568,15118,6777],{"className":15119},[6809],[568,15121],{"className":15122,"style":6813},[647],[568,15124,249],{"className":15125},[641],[568,15127,13423],{"className":15128},[955],[33,15130,15131,15133],{},[563,15132,14016],{},[30,15134,15135,15140],{},[33,15136,15137,15139],{},[563,15138,14023],{}," 1, 2, 6, 4, 7, 3, 2, 1, 4, 7",[33,15141,15142,15144],{},[563,15143,14029],{}," 10 次（总缺页14次）",[13473,15146,15148],{"id":15147},"_3-opt-最佳置换","3. OPT (最佳置换)",[26,15150,15151,15152,701],{},"初始装入 ",[568,15153,15155,15184],{"className":15154},[571],[568,15156,15158],{"className":15157},[575],[577,15159,15160],{"xmlns":579},[581,15161,15162,15182],{},[584,15163,15164,15166,15168,15170,15172,15174,15176,15178,15180],{},[591,15165,13406],{"stretchy":1061},[595,15167,249],{},[591,15169,6777],{"separator":628},[595,15171,268],{},[591,15173,6777],{"separator":628},[595,15175,287],{},[591,15177,6777],{"separator":628},[595,15179,343],{},[591,15181,13423],{"stretchy":1061},[620,15183,13426],{"encoding":622},[568,15185,15187],{"className":15186,"ariaHidden":628},[627],[568,15188,15190,15193,15196,15199,15202,15205,15208,15211,15214,15217,15220,15223,15226],{"className":15189},[632],[568,15191],{"className":15192,"style":662},[636],[568,15194,13406],{"className":15195},[872],[568,15197,249],{"className":15198},[641],[568,15200,6777],{"className":15201},[6809],[568,15203],{"className":15204,"style":6813},[647],[568,15206,268],{"className":15207},[641],[568,15209,6777],{"className":15210},[6809],[568,15212],{"className":15213,"style":6813},[647],[568,15215,287],{"className":15216},[641],[568,15218,6777],{"className":15219},[6809],[568,15221],{"className":15222,"style":6813},[647],[568,15224,343],{"className":15225},[641],[568,15227,13423],{"className":15228},[955],[30,15230,15231,15320,15409,15414,15580,15584,15749,15837,15841],{},[33,15232,15233,15235,15236,15239,15240,14125,15242,701],{},[563,15234,306],{},"：向后看后续序列 ",[1658,15237,15238],{},"(7,3,2,1,4,7,5,6,5,2,1)","。1, 2, 3 很快被用到，6 在倒数第4个才用到。",[563,15241,13750],{},[568,15243,15245,15275],{"className":15244},[571],[568,15246,15248],{"className":15247},[575],[577,15249,15250],{"xmlns":579},[581,15251,15252,15272],{},[584,15253,15254,15256,15258,15260,15262,15264,15266,15268,15270],{},[591,15255,13406],{"stretchy":1061},[595,15257,249],{},[591,15259,6777],{"separator":628},[595,15261,268],{},[591,15263,6777],{"separator":628},[595,15265,287],{},[591,15267,6777],{"separator":628},[595,15269,306],{},[591,15271,13423],{"stretchy":1061},[620,15273,15274],{"encoding":622},"\\langle1, 2, 3, 4\\rangle",[568,15276,15278],{"className":15277,"ariaHidden":628},[627],[568,15279,15281,15284,15287,15290,15293,15296,15299,15302,15305,15308,15311,15314,15317],{"className":15280},[632],[568,15282],{"className":15283,"style":662},[636],[568,15285,13406],{"className":15286},[872],[568,15288,249],{"className":15289},[641],[568,15291,6777],{"className":15292},[6809],[568,15294],{"className":15295,"style":6813},[647],[568,15297,268],{"className":15298},[641],[568,15300,6777],{"className":15301},[6809],[568,15303],{"className":15304,"style":6813},[647],[568,15306,287],{"className":15307},[641],[568,15309,6777],{"className":15310},[6809],[568,15312],{"className":15313,"style":6813},[647],[568,15315,306],{"className":15316},[641],[568,15318,13423],{"className":15319},[955],[33,15321,15322,15324,15325,15328,15329,14125,15331,701],{},[563,15323,4050],{},"：向后看 ",[1658,15326,15327],{},"(3,2,1,4,7,...)","。1, 2, 3 都比 4 先用到。",[563,15330,13842],{},[568,15332,15334,15364],{"className":15333},[571],[568,15335,15337],{"className":15336},[575],[577,15338,15339],{"xmlns":579},[581,15340,15341,15361],{},[584,15342,15343,15345,15347,15349,15351,15353,15355,15357,15359],{},[591,15344,13406],{"stretchy":1061},[595,15346,249],{},[591,15348,6777],{"separator":628},[595,15350,268],{},[591,15352,6777],{"separator":628},[595,15354,287],{},[591,15356,6777],{"separator":628},[595,15358,4050],{},[591,15360,13423],{"stretchy":1061},[620,15362,15363],{"encoding":622},"\\langle1, 2, 3, 7\\rangle",[568,15365,15367],{"className":15366,"ariaHidden":628},[627],[568,15368,15370,15373,15376,15379,15382,15385,15388,15391,15394,15397,15400,15403,15406],{"className":15369},[632],[568,15371],{"className":15372,"style":662},[636],[568,15374,13406],{"className":15375},[872],[568,15377,249],{"className":15378},[641],[568,15380,6777],{"className":15381},[6809],[568,15383],{"className":15384,"style":6813},[647],[568,15386,268],{"className":15387},[641],[568,15389,6777],{"className":15390},[6809],[568,15392],{"className":15393,"style":6813},[647],[568,15395,287],{"className":15396},[641],[568,15398,6777],{"className":15399},[6809],[568,15401],{"className":15402,"style":6813},[647],[568,15404,4050],{"className":15405},[641],[568,15407,13423],{"className":15408},[955],[33,15410,15411,13834],{},[563,15412,15413],{},"3, 2, 1",[33,15415,15416,15324,15418,15421,15422,15499,15500,14125,15502,701],{},[563,15417,306],{},[1658,15419,15420],{},"(7,5,6,5,2,1)","。当前内存 ",[568,15423,15425,15454],{"className":15424},[571],[568,15426,15428],{"className":15427},[575],[577,15429,15430],{"xmlns":579},[581,15431,15432,15452],{},[584,15433,15434,15436,15438,15440,15442,15444,15446,15448,15450],{},[591,15435,13406],{"stretchy":1061},[595,15437,249],{},[591,15439,6777],{"separator":628},[595,15441,268],{},[591,15443,6777],{"separator":628},[595,15445,287],{},[591,15447,6777],{"separator":628},[595,15449,4050],{},[591,15451,13423],{"stretchy":1061},[620,15453,15363],{"encoding":622},[568,15455,15457],{"className":15456,"ariaHidden":628},[627],[568,15458,15460,15463,15466,15469,15472,15475,15478,15481,15484,15487,15490,15493,15496],{"className":15459},[632],[568,15461],{"className":15462,"style":662},[636],[568,15464,13406],{"className":15465},[872],[568,15467,249],{"className":15468},[641],[568,15470,6777],{"className":15471},[6809],[568,15473],{"className":15474,"style":6813},[647],[568,15476,268],{"className":15477},[641],[568,15479,6777],{"className":15480},[6809],[568,15482],{"className":15483,"style":6813},[647],[568,15485,287],{"className":15486},[641],[568,15488,6777],{"className":15489},[6809],[568,15491],{"className":15492,"style":6813},[647],[568,15494,4050],{"className":15495},[641],[568,15497,13423],{"className":15498},[955]," 中，3 以后再也用不到了。",[563,15501,13664],{},[568,15503,15505,15535],{"className":15504},[571],[568,15506,15508],{"className":15507},[575],[577,15509,15510],{"xmlns":579},[581,15511,15512,15532],{},[584,15513,15514,15516,15518,15520,15522,15524,15526,15528,15530],{},[591,15515,13406],{"stretchy":1061},[595,15517,249],{},[591,15519,6777],{"separator":628},[595,15521,268],{},[591,15523,6777],{"separator":628},[595,15525,4050],{},[591,15527,6777],{"separator":628},[595,15529,306],{},[591,15531,13423],{"stretchy":1061},[620,15533,15534],{"encoding":622},"\\langle1, 2, 7, 4\\rangle",[568,15536,15538],{"className":15537,"ariaHidden":628},[627],[568,15539,15541,15544,15547,15550,15553,15556,15559,15562,15565,15568,15571,15574,15577],{"className":15540},[632],[568,15542],{"className":15543,"style":662},[636],[568,15545,13406],{"className":15546},[872],[568,15548,249],{"className":15549},[641],[568,15551,6777],{"className":15552},[6809],[568,15554],{"className":15555,"style":6813},[647],[568,15557,268],{"className":15558},[641],[568,15560,6777],{"className":15561},[6809],[568,15563],{"className":15564,"style":6813},[647],[568,15566,4050],{"className":15567},[641],[568,15569,6777],{"className":15570},[6809],[568,15572],{"className":15573,"style":6813},[647],[568,15575,306],{"className":15576},[641],[568,15578,13423],{"className":15579},[955],[33,15581,15582,13656],{},[563,15583,4050],{},[33,15585,15586,15324,15588,15421,15591,15668,15669,14125,15671,701],{},[563,15587,324],{},[1658,15589,15590],{},"(6,5,2,1)",[568,15592,15594,15623],{"className":15593},[571],[568,15595,15597],{"className":15596},[575],[577,15598,15599],{"xmlns":579},[581,15600,15601,15621],{},[584,15602,15603,15605,15607,15609,15611,15613,15615,15617,15619],{},[591,15604,13406],{"stretchy":1061},[595,15606,249],{},[591,15608,6777],{"separator":628},[595,15610,268],{},[591,15612,6777],{"separator":628},[595,15614,4050],{},[591,15616,6777],{"separator":628},[595,15618,306],{},[591,15620,13423],{"stretchy":1061},[620,15622,15534],{"encoding":622},[568,15624,15626],{"className":15625,"ariaHidden":628},[627],[568,15627,15629,15632,15635,15638,15641,15644,15647,15650,15653,15656,15659,15662,15665],{"className":15628},[632],[568,15630],{"className":15631,"style":662},[636],[568,15633,13406],{"className":15634},[872],[568,15636,249],{"className":15637},[641],[568,15639,6777],{"className":15640},[6809],[568,15642],{"className":15643,"style":6813},[647],[568,15645,268],{"className":15646},[641],[568,15648,6777],{"className":15649},[6809],[568,15651],{"className":15652,"style":6813},[647],[568,15654,4050],{"className":15655},[641],[568,15657,6777],{"className":15658},[6809],[568,15660],{"className":15661,"style":6813},[647],[568,15663,306],{"className":15664},[641],[568,15666,13423],{"className":15667},[955]," 中，4 再也用不到了，淘汰 4。",[563,15670,13842],{},[568,15672,15674,15704],{"className":15673},[571],[568,15675,15677],{"className":15676},[575],[577,15678,15679],{"xmlns":579},[581,15680,15681,15701],{},[584,15682,15683,15685,15687,15689,15691,15693,15695,15697,15699],{},[591,15684,13406],{"stretchy":1061},[595,15686,249],{},[591,15688,6777],{"separator":628},[595,15690,268],{},[591,15692,6777],{"separator":628},[595,15694,4050],{},[591,15696,6777],{"separator":628},[595,15698,324],{},[591,15700,13423],{"stretchy":1061},[620,15702,15703],{"encoding":622},"\\langle1, 2, 7, 5\\rangle",[568,15705,15707],{"className":15706,"ariaHidden":628},[627],[568,15708,15710,15713,15716,15719,15722,15725,15728,15731,15734,15737,15740,15743,15746],{"className":15709},[632],[568,15711],{"className":15712,"style":662},[636],[568,15714,13406],{"className":15715},[872],[568,15717,249],{"className":15718},[641],[568,15720,6777],{"className":15721},[6809],[568,15723],{"className":15724,"style":6813},[647],[568,15726,268],{"className":15727},[641],[568,15729,6777],{"className":15730},[6809],[568,15732],{"className":15733,"style":6813},[647],[568,15735,4050],{"className":15736},[641],[568,15738,6777],{"className":15739},[6809],[568,15741],{"className":15742,"style":6813},[647],[568,15744,324],{"className":15745},[641],[568,15747,13423],{"className":15748},[955],[33,15750,15751,15324,15753,15756,15757,14125,15759,701],{},[563,15752,343],{},[1658,15754,15755],{},"(5,2,1)","。7 再也用不到了。",[563,15758,13928],{},[568,15760,15762,15792],{"className":15761},[571],[568,15763,15765],{"className":15764},[575],[577,15766,15767],{"xmlns":579},[581,15768,15769,15789],{},[584,15770,15771,15773,15775,15777,15779,15781,15783,15785,15787],{},[591,15772,13406],{"stretchy":1061},[595,15774,249],{},[591,15776,6777],{"separator":628},[595,15778,268],{},[591,15780,6777],{"separator":628},[595,15782,324],{},[591,15784,6777],{"separator":628},[595,15786,343],{},[591,15788,13423],{"stretchy":1061},[620,15790,15791],{"encoding":622},"\\langle1, 2, 5, 6\\rangle",[568,15793,15795],{"className":15794,"ariaHidden":628},[627],[568,15796,15798,15801,15804,15807,15810,15813,15816,15819,15822,15825,15828,15831,15834],{"className":15797},[632],[568,15799],{"className":15800,"style":662},[636],[568,15802,13406],{"className":15803},[872],[568,15805,249],{"className":15806},[641],[568,15808,6777],{"className":15809},[6809],[568,15811],{"className":15812,"style":6813},[647],[568,15814,268],{"className":15815},[641],[568,15817,6777],{"className":15818},[6809],[568,15820],{"className":15821,"style":6813},[647],[568,15823,324],{"className":15824},[641],[568,15826,6777],{"className":15827},[6809],[568,15829],{"className":15830,"style":6813},[647],[568,15832,343],{"className":15833},[641],[568,15835,13423],{"className":15836},[955],[33,15838,15839,13834],{},[563,15840,14011],{},[33,15842,15843,15845],{},[563,15844,14016],{},[30,15846,15847,15852],{},[33,15848,15849,15851],{},[563,15850,14023],{}," 6, 4, 3, 4, 7",[33,15853,15854,15856],{},[563,15855,14029],{}," 5 次（总缺页9次）",[554,15858,15860],{"id":15859},"常见易错点-common-pitfalls","常见易错点 (Common Pitfalls)",[26,15862,15863],{},"在 LRU 算法中，一旦某个页面\"命中（Hit）\"，一定要记得将其\"新鲜度\"提升到最高。很多同学在发生命中时忘记更新该页面的时间戳，导致后续淘汰了错误的页面。\n:::",[13,15865,15867],{"id":15866},"_51-旋转型磁盘-io-优化分布计算","51. 旋转型磁盘 I\u002FO 优化分布计算",[26,15869,15870],{},"旋转型磁盘上的信息优化分布能减少若干 I\u002FO 服务的总时间。假如有 13 个记录存放在磁盘的某一磁道上，每个磁道划分成 13 块，每块存放一个记录，如图所示。磁盘旋转速度为 30ms 转 1 周，处理程序每读一个记录后花 5ms 进行处理。",[53,15872,15873,15908],{},[56,15874,15875],{},[59,15876,15877,15880,15882,15884,15886,15888,15890,15892,15894,15896,15898,15900,15903,15905],{},[62,15878,15879],{"align":64},"块号",[62,15881,249],{"align":64},[62,15883,268],{"align":64},[62,15885,287],{"align":64},[62,15887,306],{"align":64},[62,15889,324],{"align":64},[62,15891,343],{"align":64},[62,15893,4050],{"align":64},[62,15895,1218],{"align":64},[62,15897,735],{"align":64},[62,15899,330],{"align":64},[62,15901,15902],{"align":64},"11",[62,15904,3694],{"align":64},[62,15906,15907],{"align":64},"13",[73,15909,15910],{},[59,15911,15912,15915,15918,15921,15924,15927,15930,15933,15936,15939,15942,15945,15948,15951],{},[78,15913,15914],{"align":64},"记录",[78,15916,15917],{"align":64},"R1",[78,15919,15920],{"align":64},"R2",[78,15922,15923],{"align":64},"R3",[78,15925,15926],{"align":64},"R4",[78,15928,15929],{"align":64},"R5",[78,15931,15932],{"align":64},"R6",[78,15934,15935],{"align":64},"R7",[78,15937,15938],{"align":64},"R8",[78,15940,15941],{"align":64},"R9",[78,15943,15944],{"align":64},"R10",[78,15946,15947],{"align":64},"R11",[78,15949,15950],{"align":64},"R12",[78,15952,15953],{"align":64},"R13",[30,15955,15956,15959],{},[33,15957,15958],{},"（1）处理完 13 个记录的总时间是多少？",[33,15960,15961],{},"（2）为缩短处理时间应如何排列这些记录？计算重新排列后的总时间。",[26,15963,41],{},[554,15965,9524],{"id":15966},"概念核对-concept-check-2",[30,15968,15969,16128,16224],{},[33,15970,15971,16069,16070,16127],{},[563,15972,15973,15974,16068],{},"单块读取时间 (",[568,15975,15977,16004],{"className":15976},[571],[568,15978,15980],{"className":15979},[575],[577,15981,15982],{"xmlns":579},[581,15983,15984,16001],{},[584,15985,15986],{},[4138,15987,15988,15990],{},[587,15989,722],{},[584,15991,15992,15995,15997,15999],{},[587,15993,15994],{},"r",[587,15996,4158],{},[587,15998,4150],{},[587,16000,4732],{},[620,16002,16003],{"encoding":622},"t_{read}",[568,16005,16007],{"className":16006,"ariaHidden":628},[627],[568,16008,16010,16014],{"className":16009},[632],[568,16011],{"className":16012,"style":16013},[636],"height:0.7651em;vertical-align:-0.15em;",[568,16015,16017,16020],{"className":16016},[641],[568,16018,722],{"className":16019},[641,642],[568,16021,16023],{"className":16022},[4197],[568,16024,16026,16060],{"className":16025},[880,881],[568,16027,16029,16057],{"className":16028},[885],[568,16030,16032],{"className":16031,"style":4207},[889],[568,16033,16035,16038],{"style":16034},"top:-2.55em;margin-left:0em;margin-right:0.05em;",[568,16036],{"className":16037,"style":4214},[897],[568,16039,16041],{"className":16040},[902,903,904,905],[568,16042,16044,16048,16051,16054],{"className":16043},[641,905],[568,16045,15994],{"className":16046,"style":16047},[641,642,905],"margin-right:0.0278em;",[568,16049,4158],{"className":16050},[641,642,905],[568,16052,4150],{"className":16053},[641,642,905],[568,16055,4732],{"className":16056},[641,642,905],[568,16058,942],{"className":16059},[941],[568,16061,16063],{"className":16062},[885],[568,16064,16066],{"className":16065,"style":4245},[889],[568,16067],{},")："," 磁盘转 1 周 30ms，共 13 块，读取 1 块的时间为 ",[568,16071,16073,16096],{"className":16072},[571],[568,16074,16076],{"className":16075},[575],[577,16077,16078],{"xmlns":579},[581,16079,16080,16093],{},[584,16081,16082,16084,16086,16088,16090],{},[595,16083,274],{},[587,16085,607],{"mathvariant":606},[595,16087,15907],{},[591,16089,738],{},[595,16091,16092],{},"2.31",[620,16094,16095],{"encoding":622},"30 \u002F 13 \\approx 2.31",[568,16097,16099,16118],{"className":16098,"ariaHidden":628},[627],[568,16100,16102,16105,16109,16112,16115],{"className":16101},[632],[568,16103],{"className":16104,"style":662},[636],[568,16106,16108],{"className":16107},[641],"30\u002F13",[568,16110],{"className":16111,"style":648},[647],[568,16113,738],{"className":16114},[652],[568,16116],{"className":16117,"style":648},[647],[568,16119,16121,16124],{"className":16120},[632],[568,16122],{"className":16123,"style":691},[636],[568,16125,16092],{"className":16126},[641]," ms。",[33,16129,16130,16223],{},[563,16131,16132,16133,16068],{},"处理时间 (",[568,16134,16136,16162],{"className":16135},[571],[568,16137,16139],{"className":16138},[575],[577,16140,16141],{"xmlns":579},[581,16142,16143,16159],{},[584,16144,16145],{},[4138,16146,16147,16149],{},[587,16148,722],{},[584,16150,16151,16153,16155,16157],{},[587,16152,26],{},[587,16154,15994],{},[587,16156,12089],{},[587,16158,4147],{},[620,16160,16161],{"encoding":622},"t_{proc}",[568,16163,16165],{"className":16164,"ariaHidden":628},[627],[568,16166,16168,16172],{"className":16167},[632],[568,16169],{"className":16170,"style":16171},[636],"height:0.9012em;vertical-align:-0.2861em;",[568,16173,16175,16178],{"className":16174},[641],[568,16176,722],{"className":16177},[641,642],[568,16179,16181],{"className":16180},[4197],[568,16182,16184,16214],{"className":16183},[880,881],[568,16185,16187,16211],{"className":16186},[885],[568,16188,16190],{"className":16189,"style":4448},[889],[568,16191,16192,16195],{"style":16034},[568,16193],{"className":16194,"style":4214},[897],[568,16196,16198],{"className":16197},[902,903,904,905],[568,16199,16201,16204,16207],{"className":16200},[641,905],[568,16202,26],{"className":16203},[641,642,905],[568,16205,15994],{"className":16206,"style":16047},[641,642,905],[568,16208,16210],{"className":16209},[641,642,905],"oc",[568,16212,942],{"className":16213},[941],[568,16215,16217],{"className":16216},[885],[568,16218,16221],{"className":16219,"style":16220},[889],"height:0.2861em;",[568,16222],{}," 每读完一个记录后，CPU 需花费 5ms 处理。",[33,16225,16226,16227,16230],{},"磁盘在 CPU 处理记录时",[563,16228,16229],{},"不会停止旋转","。如果在处理完毕后，磁头已经错过了下一个逻辑记录的开头，就必须等待磁盘再转一圈才能读取。",[554,16232,13388],{"id":16233},"原理解析与计算过程-1",[13473,16235,16237],{"id":16236},"_1处理完-13-个记录的总时间未优化","（1）处理完 13 个记录的总时间（未优化）",[9640,16239,16240,16735,17045],{},[33,16241,16242,16245,16246,16316,16317,16349,16350,16419,16420,16448,16449,16477,16478,16593,16594,16663,16664,16734],{},[563,16243,16244],{},"分析单次循环：","\n读取 ",[568,16247,16249,16267],{"className":16248},[571],[568,16250,16252],{"className":16251},[575],[577,16253,16254],{"xmlns":579},[581,16255,16256,16264],{},[584,16257,16258],{},[4138,16259,16260,16262],{},[587,16261,8424],{},[595,16263,249],{},[620,16265,16266],{"encoding":622},"R_1",[568,16268,16270],{"className":16269,"ariaHidden":628},[627],[568,16271,16273,16276],{"className":16272},[632],[568,16274],{"className":16275,"style":4187},[636],[568,16277,16279,16282],{"className":16278},[641],[568,16280,8424],{"className":16281,"style":8459},[641,642],[568,16283,16285],{"className":16284},[4197],[568,16286,16288,16308],{"className":16287},[880,881],[568,16289,16291,16305],{"className":16290},[885],[568,16292,16294],{"className":16293,"style":10008},[889],[568,16295,16296,16299],{"style":8475},[568,16297],{"className":16298,"style":4214},[897],[568,16300,16302],{"className":16301},[902,903,904,905],[568,16303,249],{"className":16304},[641,905],[568,16306,942],{"className":16307},[941],[568,16309,16311],{"className":16310},[885],[568,16312,16314],{"className":16313,"style":4245},[889],[568,16315],{}," 需要 ",[568,16318,16320,16337],{"className":16319},[571],[568,16321,16323],{"className":16322},[575],[577,16324,16325],{"xmlns":579},[581,16326,16327,16335],{},[584,16328,16329,16331,16333],{},[595,16330,274],{},[587,16332,607],{"mathvariant":606},[595,16334,15907],{},[620,16336,16108],{"encoding":622},[568,16338,16340],{"className":16339,"ariaHidden":628},[627],[568,16341,16343,16346],{"className":16342},[632],[568,16344],{"className":16345,"style":662},[636],[568,16347,16108],{"className":16348},[641]," ms。读取结束后，磁头位于第 2 块的开头。此时 CPU 开始处理 ",[568,16351,16353,16370],{"className":16352},[571],[568,16354,16356],{"className":16355},[575],[577,16357,16358],{"xmlns":579},[581,16359,16360,16368],{},[584,16361,16362],{},[4138,16363,16364,16366],{},[587,16365,8424],{},[595,16367,249],{},[620,16369,16266],{"encoding":622},[568,16371,16373],{"className":16372,"ariaHidden":628},[627],[568,16374,16376,16379],{"className":16375},[632],[568,16377],{"className":16378,"style":4187},[636],[568,16380,16382,16385],{"className":16381},[641],[568,16383,8424],{"className":16384,"style":8459},[641,642],[568,16386,16388],{"className":16387},[4197],[568,16389,16391,16411],{"className":16390},[880,881],[568,16392,16394,16408],{"className":16393},[885],[568,16395,16397],{"className":16396,"style":10008},[889],[568,16398,16399,16402],{"style":8475},[568,16400],{"className":16401,"style":4214},[897],[568,16403,16405],{"className":16404},[902,903,904,905],[568,16406,249],{"className":16407},[641,905],[568,16409,942],{"className":16410},[941],[568,16412,16414],{"className":16413},[885],[568,16415,16417],{"className":16416,"style":4245},[889],[568,16418],{},"，耗时 ",[568,16421,16423,16436],{"className":16422},[571],[568,16424,16426],{"className":16425},[575],[577,16427,16428],{"xmlns":579},[581,16429,16430,16434],{},[584,16431,16432],{},[595,16433,324],{},[620,16435,324],{"encoding":622},[568,16437,16439],{"className":16438,"ariaHidden":628},[627],[568,16440,16442,16445],{"className":16441},[632],[568,16443],{"className":16444,"style":691},[636],[568,16446,324],{"className":16447},[641]," ms。\n在这 ",[568,16450,16452,16465],{"className":16451},[571],[568,16453,16455],{"className":16454},[575],[577,16456,16457],{"xmlns":579},[581,16458,16459,16463],{},[584,16460,16461],{},[595,16462,324],{},[620,16464,324],{"encoding":622},[568,16466,16468],{"className":16467,"ariaHidden":628},[627],[568,16469,16471,16474],{"className":16470},[632],[568,16472],{"className":16473,"style":691},[636],[568,16475,324],{"className":16476},[641]," ms 内，磁盘转过了 ",[568,16479,16481,16520],{"className":16480},[571],[568,16482,16484],{"className":16483},[575],[577,16485,16486],{"xmlns":579},[581,16487,16488,16517],{},[584,16489,16490,16492,16494,16496,16498,16500,16502,16504,16506,16508,16510,16512,16514],{},[595,16491,324],{},[591,16493,9662],{},[591,16495,1062],{"stretchy":1061},[595,16497,274],{},[587,16499,607],{"mathvariant":606},[595,16501,15907],{},[591,16503,1071],{"stretchy":1061},[591,16505,593],{},[595,16507,8675],{},[587,16509,607],{"mathvariant":606},[595,16511,274],{},[591,16513,593],{},[595,16515,16516],{},"2.16",[620,16518,16519],{"encoding":622},"5 \\div (30\u002F13) = 65\u002F30 = 2.16",[568,16521,16523,16541,16565,16584],{"className":16522,"ariaHidden":628},[627],[568,16524,16526,16529,16532,16535,16538],{"className":16525},[632],[568,16527],{"className":16528,"style":1249},[636],[568,16530,324],{"className":16531},[641],[568,16533],{"className":16534,"style":1256},[647],[568,16536,9662],{"className":16537},[1260],[568,16539],{"className":16540,"style":1256},[647],[568,16542,16544,16547,16550,16553,16556,16559,16562],{"className":16543},[632],[568,16545],{"className":16546,"style":662},[636],[568,16548,1062],{"className":16549},[872],[568,16551,16108],{"className":16552},[641],[568,16554,1071],{"className":16555},[955],[568,16557],{"className":16558,"style":648},[647],[568,16560,593],{"className":16561},[652],[568,16563],{"className":16564,"style":648},[647],[568,16566,16568,16571,16575,16578,16581],{"className":16567},[632],[568,16569],{"className":16570,"style":662},[636],[568,16572,16574],{"className":16573},[641],"65\u002F30",[568,16576],{"className":16577,"style":648},[647],[568,16579,593],{"className":16580},[652],[568,16582],{"className":16583,"style":648},[647],[568,16585,16587,16590],{"className":16586},[632],[568,16588],{"className":16589,"style":691},[636],[568,16591,16516],{"className":16592},[641]," 块。\n也就是说，当 CPU 处理完 ",[568,16595,16597,16614],{"className":16596},[571],[568,16598,16600],{"className":16599},[575],[577,16601,16602],{"xmlns":579},[581,16603,16604,16612],{},[584,16605,16606],{},[4138,16607,16608,16610],{},[587,16609,8424],{},[595,16611,249],{},[620,16613,16266],{"encoding":622},[568,16615,16617],{"className":16616,"ariaHidden":628},[627],[568,16618,16620,16623],{"className":16619},[632],[568,16621],{"className":16622,"style":4187},[636],[568,16624,16626,16629],{"className":16625},[641],[568,16627,8424],{"className":16628,"style":8459},[641,642],[568,16630,16632],{"className":16631},[4197],[568,16633,16635,16655],{"className":16634},[880,881],[568,16636,16638,16652],{"className":16637},[885],[568,16639,16641],{"className":16640,"style":10008},[889],[568,16642,16643,16646],{"style":8475},[568,16644],{"className":16645,"style":4214},[897],[568,16647,16649],{"className":16648},[902,903,904,905],[568,16650,249],{"className":16651},[641,905],[568,16653,942],{"className":16654},[941],[568,16656,16658],{"className":16657},[885],[568,16659,16661],{"className":16660,"style":4245},[889],[568,16662],{}," 时，磁头已经越过了第 2 块、第 3 块，正处于第 4 块的上方。\n此时 CPU 想要读取连续存放的 ",[568,16665,16667,16685],{"className":16666},[571],[568,16668,16670],{"className":16669},[575],[577,16671,16672],{"xmlns":579},[581,16673,16674,16682],{},[584,16675,16676],{},[4138,16677,16678,16680],{},[587,16679,8424],{},[595,16681,268],{},[620,16683,16684],{"encoding":622},"R_2",[568,16686,16688],{"className":16687,"ariaHidden":628},[627],[568,16689,16691,16694],{"className":16690},[632],[568,16692],{"className":16693,"style":4187},[636],[568,16695,16697,16700],{"className":16696},[641],[568,16698,8424],{"className":16699,"style":8459},[641,642],[568,16701,16703],{"className":16702},[4197],[568,16704,16706,16726],{"className":16705},[880,881],[568,16707,16709,16723],{"className":16708},[885],[568,16710,16712],{"className":16711,"style":10008},[889],[568,16713,16714,16717],{"style":8475},[568,16715],{"className":16716,"style":4214},[897],[568,16718,16720],{"className":16719},[902,903,904,905],[568,16721,268],{"className":16722},[641,905],[568,16724,942],{"className":16725},[941],[568,16727,16729],{"className":16728},[885],[568,16730,16732],{"className":16731,"style":4245},[889],[568,16733],{},"（位于第 2 块），必须等待磁盘继续旋转，直到第 2 块的开头再次来到磁头下方。",[33,16736,16737,16831,16832,16901,16902,16971,16972,16127],{},[563,16738,16739,16740,16068],{},"计算等待时间 (",[568,16741,16743,16770],{"className":16742},[571],[568,16744,16746],{"className":16745},[575],[577,16747,16748],{"xmlns":579},[581,16749,16750,16767],{},[584,16751,16752],{},[4138,16753,16754,16756],{},[587,16755,722],{},[584,16757,16758,16761,16763,16765],{},[587,16759,16760],{},"w",[587,16762,4150],{},[587,16764,4735],{},[587,16766,722],{},[620,16768,16769],{"encoding":622},"t_{wait}",[568,16771,16773],{"className":16772,"ariaHidden":628},[627],[568,16774,16776,16779],{"className":16775},[632],[568,16777],{"className":16778,"style":16013},[636],[568,16780,16782,16785],{"className":16781},[641],[568,16783,722],{"className":16784},[641,642],[568,16786,16788],{"className":16787},[4197],[568,16789,16791,16823],{"className":16790},[880,881],[568,16792,16794,16820],{"className":16793},[885],[568,16795,16798],{"className":16796,"style":16797},[889],"height:0.3117em;",[568,16799,16800,16803],{"style":16034},[568,16801],{"className":16802,"style":4214},[897],[568,16804,16806],{"className":16805},[902,903,904,905],[568,16807,16809,16813,16817],{"className":16808},[641,905],[568,16810,16760],{"className":16811,"style":16812},[641,642,905],"margin-right:0.0269em;",[568,16814,16816],{"className":16815},[641,642,905],"ai",[568,16818,722],{"className":16819},[641,642,905],[568,16821,942],{"className":16822},[941],[568,16824,16826],{"className":16825},[885],[568,16827,16829],{"className":16828,"style":4245},[889],[568,16830],{},"\n从读取 ",[568,16833,16835,16852],{"className":16834},[571],[568,16836,16838],{"className":16837},[575],[577,16839,16840],{"xmlns":579},[581,16841,16842,16850],{},[584,16843,16844],{},[4138,16845,16846,16848],{},[587,16847,8424],{},[595,16849,249],{},[620,16851,16266],{"encoding":622},[568,16853,16855],{"className":16854,"ariaHidden":628},[627],[568,16856,16858,16861],{"className":16857},[632],[568,16859],{"className":16860,"style":4187},[636],[568,16862,16864,16867],{"className":16863},[641],[568,16865,8424],{"className":16866,"style":8459},[641,642],[568,16868,16870],{"className":16869},[4197],[568,16871,16873,16893],{"className":16872},[880,881],[568,16874,16876,16890],{"className":16875},[885],[568,16877,16879],{"className":16878,"style":10008},[889],[568,16880,16881,16884],{"style":8475},[568,16882],{"className":16883,"style":4214},[897],[568,16885,16887],{"className":16886},[902,903,904,905],[568,16888,249],{"className":16889},[641,905],[568,16891,942],{"className":16892},[941],[568,16894,16896],{"className":16895},[885],[568,16897,16899],{"className":16898,"style":4245},[889],[568,16900],{}," 结束 到 再次遇到 ",[568,16903,16905,16922],{"className":16904},[571],[568,16906,16908],{"className":16907},[575],[577,16909,16910],{"xmlns":579},[581,16911,16912,16920],{},[584,16913,16914],{},[4138,16915,16916,16918],{},[587,16917,8424],{},[595,16919,268],{},[620,16921,16684],{"encoding":622},[568,16923,16925],{"className":16924,"ariaHidden":628},[627],[568,16926,16928,16931],{"className":16927},[632],[568,16929],{"className":16930,"style":4187},[636],[568,16932,16934,16937],{"className":16933},[641],[568,16935,8424],{"className":16936,"style":8459},[641,642],[568,16938,16940],{"className":16939},[4197],[568,16941,16943,16963],{"className":16942},[880,881],[568,16944,16946,16960],{"className":16945},[885],[568,16947,16949],{"className":16948,"style":10008},[889],[568,16950,16951,16954],{"style":8475},[568,16952],{"className":16953,"style":4214},[897],[568,16955,16957],{"className":16956},[902,903,904,905],[568,16958,268],{"className":16959},[641,905],[568,16961,942],{"className":16962},[941],[568,16964,16966],{"className":16965},[885],[568,16967,16969],{"className":16968,"style":4245},[889],[568,16970],{}," 开头，磁盘正好需要转动一整圈（30ms）。\n因为 CPU 处理耗去了 5ms，所以额外需要等待的时间为 ",[568,16973,16975,16997],{"className":16974},[571],[568,16976,16978],{"className":16977},[575],[577,16979,16980],{"xmlns":579},[581,16981,16982,16994],{},[584,16983,16984,16986,16988,16990,16992],{},[595,16985,274],{},[591,16987,4170],{},[595,16989,324],{},[591,16991,593],{},[595,16993,7470],{},[620,16995,16996],{"encoding":622},"30 - 5 = 25",[568,16998,17000,17018,17036],{"className":16999,"ariaHidden":628},[627],[568,17001,17003,17006,17009,17012,17015],{"className":17002},[632],[568,17004],{"className":17005,"style":1249},[636],[568,17007,274],{"className":17008},[641],[568,17010],{"className":17011,"style":1256},[647],[568,17013,4170],{"className":17014},[1260],[568,17016],{"className":17017,"style":1256},[647],[568,17019,17021,17024,17027,17030,17033],{"className":17020},[632],[568,17022],{"className":17023,"style":691},[636],[568,17025,324],{"className":17026},[641],[568,17028],{"className":17029,"style":648},[647],[568,17031,593],{"className":17032},[652],[568,17034],{"className":17035,"style":648},[647],[568,17037,17039,17042],{"className":17038},[632],[568,17040],{"className":17041,"style":691},[636],[568,17043,7470],{"className":17044},[641],[33,17046,17047,17050,17051,17220,17221,17294,17295,17441,17442,1491,17444,16127],{},[563,17048,17049],{},"计算总时间：","\n对于前 12 个记录，每个记录的周期 = 读取 + 处理 + 等待 = ",[568,17052,17054,17089],{"className":17053},[571],[568,17055,17057],{"className":17056},[575],[577,17058,17059],{"xmlns":579},[581,17060,17061,17086],{},[584,17062,17063,17065,17067,17069,17071,17073,17075,17077,17079],{},[595,17064,274],{},[587,17066,607],{"mathvariant":606},[595,17068,15907],{},[591,17070,1508],{},[595,17072,324],{},[591,17074,1508],{},[595,17076,7470],{},[591,17078,593],{},[843,17080,17081,17084],{},[595,17082,17083],{},"420",[595,17085,15907],{},[620,17087,17088],{"encoding":622},"30\u002F13 + 5 + 25 = \\frac{420}{13}",[568,17090,17092,17110,17128,17146],{"className":17091,"ariaHidden":628},[627],[568,17093,17095,17098,17101,17104,17107],{"className":17094},[632],[568,17096],{"className":17097,"style":662},[636],[568,17099,16108],{"className":17100},[641],[568,17102],{"className":17103,"style":1256},[647],[568,17105,1508],{"className":17106},[1260],[568,17108],{"className":17109,"style":1256},[647],[568,17111,17113,17116,17119,17122,17125],{"className":17112},[632],[568,17114],{"className":17115,"style":1249},[636],[568,17117,324],{"className":17118},[641],[568,17120],{"className":17121,"style":1256},[647],[568,17123,1508],{"className":17124},[1260],[568,17126],{"className":17127,"style":1256},[647],[568,17129,17131,17134,17137,17140,17143],{"className":17130},[632],[568,17132],{"className":17133,"style":691},[636],[568,17135,7470],{"className":17136},[641],[568,17138],{"className":17139,"style":648},[647],[568,17141,593],{"className":17142},[652],[568,17144],{"className":17145,"style":648},[647],[568,17147,17149,17152],{"className":17148},[632],[568,17150],{"className":17151,"style":865},[636],[568,17153,17155,17158,17217],{"className":17154},[641],[568,17156],{"className":17157},[872,873],[568,17159,17161],{"className":17160},[843],[568,17162,17164,17209],{"className":17163},[880,881],[568,17165,17167,17206],{"className":17166},[885],[568,17168,17170,17184,17192],{"className":17169,"style":890},[889],[568,17171,17172,17175],{"style":893},[568,17173],{"className":17174,"style":898},[897],[568,17176,17178],{"className":17177},[902,903,904,905],[568,17179,17181],{"className":17180},[641,905],[568,17182,15907],{"className":17183},[641,905],[568,17185,17186,17189],{"style":914},[568,17187],{"className":17188,"style":898},[897],[568,17190],{"className":17191,"style":922},[921],[568,17193,17194,17197],{"style":925},[568,17195],{"className":17196,"style":898},[897],[568,17198,17200],{"className":17199},[902,903,904,905],[568,17201,17203],{"className":17202},[641,905],[568,17204,17083],{"className":17205},[641,905],[568,17207,942],{"className":17208},[941],[568,17210,17212],{"className":17211},[885],[568,17213,17215],{"className":17214,"style":949},[889],[568,17216],{},[568,17218],{"className":17219},[955,873]," ms。\n对于最后 1 个记录（",[568,17222,17224,17242],{"className":17223},[571],[568,17225,17227],{"className":17226},[575],[577,17228,17229],{"xmlns":579},[581,17230,17231,17239],{},[584,17232,17233],{},[4138,17234,17235,17237],{},[587,17236,8424],{},[595,17238,15907],{},[620,17240,17241],{"encoding":622},"R_{13}",[568,17243,17245],{"className":17244,"ariaHidden":628},[627],[568,17246,17248,17251],{"className":17247},[632],[568,17249],{"className":17250,"style":4187},[636],[568,17252,17254,17257],{"className":17253},[641],[568,17255,8424],{"className":17256,"style":8459},[641,642],[568,17258,17260],{"className":17259},[4197],[568,17261,17263,17286],{"className":17262},[880,881],[568,17264,17266,17283],{"className":17265},[885],[568,17267,17269],{"className":17268,"style":10008},[889],[568,17270,17271,17274],{"style":8475},[568,17272],{"className":17273,"style":4214},[897],[568,17275,17277],{"className":17276},[902,903,904,905],[568,17278,17280],{"className":17279},[641,905],[568,17281,15907],{"className":17282},[641,905],[568,17284,942],{"className":17285},[941],[568,17287,17289],{"className":17288},[885],[568,17290,17292],{"className":17291,"style":4245},[889],[568,17293],{},"），读完并处理完即结束，不需要再等待。耗时 = ",[568,17296,17298,17328],{"className":17297},[571],[568,17299,17301],{"className":17300},[575],[577,17302,17303],{"xmlns":579},[581,17304,17305,17325],{},[584,17306,17307,17309,17311,17313,17315,17317,17319],{},[595,17308,274],{},[587,17310,607],{"mathvariant":606},[595,17312,15907],{},[591,17314,1508],{},[595,17316,324],{},[591,17318,593],{},[843,17320,17321,17323],{},[595,17322,8715],{},[595,17324,15907],{},[620,17326,17327],{"encoding":622},"30\u002F13 + 5 = \\frac{95}{13}",[568,17329,17331,17349,17367],{"className":17330,"ariaHidden":628},[627],[568,17332,17334,17337,17340,17343,17346],{"className":17333},[632],[568,17335],{"className":17336,"style":662},[636],[568,17338,16108],{"className":17339},[641],[568,17341],{"className":17342,"style":1256},[647],[568,17344,1508],{"className":17345},[1260],[568,17347],{"className":17348,"style":1256},[647],[568,17350,17352,17355,17358,17361,17364],{"className":17351},[632],[568,17353],{"className":17354,"style":691},[636],[568,17356,324],{"className":17357},[641],[568,17359],{"className":17360,"style":648},[647],[568,17362,593],{"className":17363},[652],[568,17365],{"className":17366,"style":648},[647],[568,17368,17370,17373],{"className":17369},[632],[568,17371],{"className":17372,"style":865},[636],[568,17374,17376,17379,17438],{"className":17375},[641],[568,17377],{"className":17378},[872,873],[568,17380,17382],{"className":17381},[843],[568,17383,17385,17430],{"className":17384},[880,881],[568,17386,17388,17427],{"className":17387},[885],[568,17389,17391,17405,17413],{"className":17390,"style":890},[889],[568,17392,17393,17396],{"style":893},[568,17394],{"className":17395,"style":898},[897],[568,17397,17399],{"className":17398},[902,903,904,905],[568,17400,17402],{"className":17401},[641,905],[568,17403,15907],{"className":17404},[641,905],[568,17406,17407,17410],{"style":914},[568,17408],{"className":17409,"style":898},[897],[568,17411],{"className":17412,"style":922},[921],[568,17414,17415,17418],{"style":925},[568,17416],{"className":17417,"style":898},[897],[568,17419,17421],{"className":17420},[902,903,904,905],[568,17422,17424],{"className":17423},[641,905],[568,17425,8715],{"className":17426},[641,905],[568,17428,942],{"className":17429},[941],[568,17431,17433],{"className":17432},[885],[568,17434,17436],{"className":17435,"style":949},[889],[568,17437],{},[568,17439],{"className":17440},[955,873]," ms。\n",[563,17443,1490],{},[568,17445,17447,17495],{"className":17446},[571],[568,17448,17450],{"className":17449},[575],[577,17451,17452],{"xmlns":579},[581,17453,17454,17492],{},[584,17455,17456,17458,17460,17462,17468,17470,17472,17478,17480,17487,17489],{},[595,17457,3694],{},[591,17459,1221],{},[591,17461,1062],{"stretchy":1061},[843,17463,17464,17466],{},[595,17465,17083],{},[595,17467,15907],{},[591,17469,1071],{"stretchy":1061},[591,17471,1508],{},[843,17473,17474,17476],{},[595,17475,8715],{},[595,17477,15907],{},[591,17479,593],{},[843,17481,17482,17485],{},[595,17483,17484],{},"5135",[595,17486,15907],{},[591,17488,738],{},[595,17490,17491],{},"395",[620,17493,17494],{"encoding":622},"12 \\times (\\frac{420}{13}) + \\frac{95}{13} = \\frac{5135}{13} \\approx 395",[568,17496,17498,17516,17605,17688,17771],{"className":17497,"ariaHidden":628},[627],[568,17499,17501,17504,17507,17510,17513],{"className":17500},[632],[568,17502],{"className":17503,"style":1249},[636],[568,17505,3694],{"className":17506},[641],[568,17508],{"className":17509,"style":1256},[647],[568,17511,1221],{"className":17512},[1260],[568,17514],{"className":17515,"style":1256},[647],[568,17517,17519,17522,17525,17593,17596,17599,17602],{"className":17518},[632],[568,17520],{"className":17521,"style":865},[636],[568,17523,1062],{"className":17524},[872],[568,17526,17528,17531,17590],{"className":17527},[641],[568,17529],{"className":17530},[872,873],[568,17532,17534],{"className":17533},[843],[568,17535,17537,17582],{"className":17536},[880,881],[568,17538,17540,17579],{"className":17539},[885],[568,17541,17543,17557,17565],{"className":17542,"style":890},[889],[568,17544,17545,17548],{"style":893},[568,17546],{"className":17547,"style":898},[897],[568,17549,17551],{"className":17550},[902,903,904,905],[568,17552,17554],{"className":17553},[641,905],[568,17555,15907],{"className":17556},[641,905],[568,17558,17559,17562],{"style":914},[568,17560],{"className":17561,"style":898},[897],[568,17563],{"className":17564,"style":922},[921],[568,17566,17567,17570],{"style":925},[568,17568],{"className":17569,"style":898},[897],[568,17571,17573],{"className":17572},[902,903,904,905],[568,17574,17576],{"className":17575},[641,905],[568,17577,17083],{"className":17578},[641,905],[568,17580,942],{"className":17581},[941],[568,17583,17585],{"className":17584},[885],[568,17586,17588],{"className":17587,"style":949},[889],[568,17589],{},[568,17591],{"className":17592},[955,873],[568,17594,1071],{"className":17595},[955],[568,17597],{"className":17598,"style":1256},[647],[568,17600,1508],{"className":17601},[1260],[568,17603],{"className":17604,"style":1256},[647],[568,17606,17608,17611,17679,17682,17685],{"className":17607},[632],[568,17609],{"className":17610,"style":865},[636],[568,17612,17614,17617,17676],{"className":17613},[641],[568,17615],{"className":17616},[872,873],[568,17618,17620],{"className":17619},[843],[568,17621,17623,17668],{"className":17622},[880,881],[568,17624,17626,17665],{"className":17625},[885],[568,17627,17629,17643,17651],{"className":17628,"style":890},[889],[568,17630,17631,17634],{"style":893},[568,17632],{"className":17633,"style":898},[897],[568,17635,17637],{"className":17636},[902,903,904,905],[568,17638,17640],{"className":17639},[641,905],[568,17641,15907],{"className":17642},[641,905],[568,17644,17645,17648],{"style":914},[568,17646],{"className":17647,"style":898},[897],[568,17649],{"className":17650,"style":922},[921],[568,17652,17653,17656],{"style":925},[568,17654],{"className":17655,"style":898},[897],[568,17657,17659],{"className":17658},[902,903,904,905],[568,17660,17662],{"className":17661},[641,905],[568,17663,8715],{"className":17664},[641,905],[568,17666,942],{"className":17667},[941],[568,17669,17671],{"className":17670},[885],[568,17672,17674],{"className":17673,"style":949},[889],[568,17675],{},[568,17677],{"className":17678},[955,873],[568,17680],{"className":17681,"style":648},[647],[568,17683,593],{"className":17684},[652],[568,17686],{"className":17687,"style":648},[647],[568,17689,17691,17694,17762,17765,17768],{"className":17690},[632],[568,17692],{"className":17693,"style":865},[636],[568,17695,17697,17700,17759],{"className":17696},[641],[568,17698],{"className":17699},[872,873],[568,17701,17703],{"className":17702},[843],[568,17704,17706,17751],{"className":17705},[880,881],[568,17707,17709,17748],{"className":17708},[885],[568,17710,17712,17726,17734],{"className":17711,"style":890},[889],[568,17713,17714,17717],{"style":893},[568,17715],{"className":17716,"style":898},[897],[568,17718,17720],{"className":17719},[902,903,904,905],[568,17721,17723],{"className":17722},[641,905],[568,17724,15907],{"className":17725},[641,905],[568,17727,17728,17731],{"style":914},[568,17729],{"className":17730,"style":898},[897],[568,17732],{"className":17733,"style":922},[921],[568,17735,17736,17739],{"style":925},[568,17737],{"className":17738,"style":898},[897],[568,17740,17742],{"className":17741},[902,903,904,905],[568,17743,17745],{"className":17744},[641,905],[568,17746,17484],{"className":17747},[641,905],[568,17749,942],{"className":17750},[941],[568,17752,17754],{"className":17753},[885],[568,17755,17757],{"className":17756,"style":949},[889],[568,17758],{},[568,17760],{"className":17761},[955,873],[568,17763],{"className":17764,"style":648},[647],[568,17766,738],{"className":17767},[652],[568,17769],{"className":17770,"style":648},[647],[568,17772,17774,17777],{"className":17773},[632],[568,17775],{"className":17776,"style":691},[636],[568,17778,17491],{"className":17779},[641],[13473,17781,17783],{"id":17782},"_2重新排列记录以缩短处理时间","（2）重新排列记录以缩短处理时间",[26,17785,17786,17789,17790,17859,17860,17929,17930,17933,17934,17937],{},[563,17787,17788],{},"优化逻辑："," 为了消除高达 25ms 的无谓等待时间，我们应该把 ",[568,17791,17793,17810],{"className":17792},[571],[568,17794,17796],{"className":17795},[575],[577,17797,17798],{"xmlns":579},[581,17799,17800,17808],{},[584,17801,17802],{},[4138,17803,17804,17806],{},[587,17805,8424],{},[595,17807,268],{},[620,17809,16684],{"encoding":622},[568,17811,17813],{"className":17812,"ariaHidden":628},[627],[568,17814,17816,17819],{"className":17815},[632],[568,17817],{"className":17818,"style":4187},[636],[568,17820,17822,17825],{"className":17821},[641],[568,17823,8424],{"className":17824,"style":8459},[641,642],[568,17826,17828],{"className":17827},[4197],[568,17829,17831,17851],{"className":17830},[880,881],[568,17832,17834,17848],{"className":17833},[885],[568,17835,17837],{"className":17836,"style":10008},[889],[568,17838,17839,17842],{"style":8475},[568,17840],{"className":17841,"style":4214},[897],[568,17843,17845],{"className":17844},[902,903,904,905],[568,17846,268],{"className":17847},[641,905],[568,17849,942],{"className":17850},[941],[568,17852,17854],{"className":17853},[885],[568,17855,17857],{"className":17856,"style":4245},[889],[568,17858],{}," 放在 CPU 刚好处理完 ",[568,17861,17863,17880],{"className":17862},[571],[568,17864,17866],{"className":17865},[575],[577,17867,17868],{"xmlns":579},[581,17869,17870,17878],{},[584,17871,17872],{},[4138,17873,17874,17876],{},[587,17875,8424],{},[595,17877,249],{},[620,17879,16266],{"encoding":622},[568,17881,17883],{"className":17882,"ariaHidden":628},[627],[568,17884,17886,17889],{"className":17885},[632],[568,17887],{"className":17888,"style":4187},[636],[568,17890,17892,17895],{"className":17891},[641],[568,17893,8424],{"className":17894,"style":8459},[641,642],[568,17896,17898],{"className":17897},[4197],[568,17899,17901,17921],{"className":17900},[880,881],[568,17902,17904,17918],{"className":17903},[885],[568,17905,17907],{"className":17906,"style":10008},[889],[568,17908,17909,17912],{"style":8475},[568,17910],{"className":17911,"style":4214},[897],[568,17913,17915],{"className":17914},[902,903,904,905],[568,17916,249],{"className":17917},[641,905],[568,17919,942],{"className":17920},[941],[568,17922,17924],{"className":17923},[885],[568,17925,17927],{"className":17926,"style":4245},[889],[568,17928],{}," 时磁头所到达的那个物理块上。\n根据刚才的分析，CPU 处理耗时 5ms，相当于转过了 2.16 块。\n从第 1 块读完（处于第 2 块开头）算起，转过 2.16 块后，磁头位于第 4 块内部。因此，",[563,17931,17932],{},"下一个能从头开始完整读取的物理块是第 5 块","。\n这就意味着，物理块的",[563,17935,17936],{},"间隔应为 4","（即 1, 1+4=5, 5+4=9...）。",[9640,17939,17940,18676],{},[33,17941,17942,17945],{},[563,17943,17944],{},"最优排列方式（按物理块1~13列出记录）：",[568,17946,17948,18062],{"className":17947},[571],[568,17949,17951],{"className":17950},[575],[577,17952,17953],{"xmlns":579},[581,17954,17955,18059],{},[584,17956,17957,17963,17965,17971,17973,17979,17981,17987,17989,17995,17997,18003,18005,18011,18013,18019,18021,18027,18029,18035,18037,18043,18045,18051,18053],{},[4138,17958,17959,17961],{},[587,17960,8424],{},[595,17962,249],{},[591,17964,6777],{"separator":628},[4138,17966,17967,17969],{},[587,17968,8424],{},[595,17970,15902],{},[591,17972,6777],{"separator":628},[4138,17974,17975,17977],{},[587,17976,8424],{},[595,17978,1218],{},[591,17980,6777],{"separator":628},[4138,17982,17983,17985],{},[587,17984,8424],{},[595,17986,324],{},[591,17988,6777],{"separator":628},[4138,17990,17991,17993],{},[587,17992,8424],{},[595,17994,268],{},[591,17996,6777],{"separator":628},[4138,17998,17999,18001],{},[587,18000,8424],{},[595,18002,3694],{},[591,18004,6777],{"separator":628},[4138,18006,18007,18009],{},[587,18008,8424],{},[595,18010,735],{},[591,18012,6777],{"separator":628},[4138,18014,18015,18017],{},[587,18016,8424],{},[595,18018,343],{},[591,18020,6777],{"separator":628},[4138,18022,18023,18025],{},[587,18024,8424],{},[595,18026,287],{},[591,18028,6777],{"separator":628},[4138,18030,18031,18033],{},[587,18032,8424],{},[595,18034,15907],{},[591,18036,6777],{"separator":628},[4138,18038,18039,18041],{},[587,18040,8424],{},[595,18042,330],{},[591,18044,6777],{"separator":628},[4138,18046,18047,18049],{},[587,18048,8424],{},[595,18050,4050],{},[591,18052,6777],{"separator":628},[4138,18054,18055,18057],{},[587,18056,8424],{},[595,18058,306],{},[620,18060,18061],{"encoding":622},"R_1, R_{11}, R_8, R_5, R_2, R_{12}, R_9, R_6, R_3, R_{13}, R_{10}, R_7, R_4",[568,18063,18065],{"className":18064,"ariaHidden":628},[627],[568,18066,18068,18072,18112,18115,18118,18161,18164,18167,18207,18210,18213,18253,18256,18259,18299,18302,18305,18348,18351,18354,18394,18397,18400,18440,18443,18446,18486,18489,18492,18535,18538,18541,18584,18587,18590,18630,18633,18636],{"className":18067},[632],[568,18069],{"className":18070,"style":18071},[636],"height:0.8778em;vertical-align:-0.1944em;",[568,18073,18075,18078],{"className":18074},[641],[568,18076,8424],{"className":18077,"style":8459},[641,642],[568,18079,18081],{"className":18080},[4197],[568,18082,18084,18104],{"className":18083},[880,881],[568,18085,18087,18101],{"className":18086},[885],[568,18088,18090],{"className":18089,"style":10008},[889],[568,18091,18092,18095],{"style":8475},[568,18093],{"className":18094,"style":4214},[897],[568,18096,18098],{"className":18097},[902,903,904,905],[568,18099,249],{"className":18100},[641,905],[568,18102,942],{"className":18103},[941],[568,18105,18107],{"className":18106},[885],[568,18108,18110],{"className":18109,"style":4245},[889],[568,18111],{},[568,18113,6777],{"className":18114},[6809],[568,18116],{"className":18117,"style":6813},[647],[568,18119,18121,18124],{"className":18120},[641],[568,18122,8424],{"className":18123,"style":8459},[641,642],[568,18125,18127],{"className":18126},[4197],[568,18128,18130,18153],{"className":18129},[880,881],[568,18131,18133,18150],{"className":18132},[885],[568,18134,18136],{"className":18135,"style":10008},[889],[568,18137,18138,18141],{"style":8475},[568,18139],{"className":18140,"style":4214},[897],[568,18142,18144],{"className":18143},[902,903,904,905],[568,18145,18147],{"className":18146},[641,905],[568,18148,15902],{"className":18149},[641,905],[568,18151,942],{"className":18152},[941],[568,18154,18156],{"className":18155},[885],[568,18157,18159],{"className":18158,"style":4245},[889],[568,18160],{},[568,18162,6777],{"className":18163},[6809],[568,18165],{"className":18166,"style":6813},[647],[568,18168,18170,18173],{"className":18169},[641],[568,18171,8424],{"className":18172,"style":8459},[641,642],[568,18174,18176],{"className":18175},[4197],[568,18177,18179,18199],{"className":18178},[880,881],[568,18180,18182,18196],{"className":18181},[885],[568,18183,18185],{"className":18184,"style":10008},[889],[568,18186,18187,18190],{"style":8475},[568,18188],{"className":18189,"style":4214},[897],[568,18191,18193],{"className":18192},[902,903,904,905],[568,18194,1218],{"className":18195},[641,905],[568,18197,942],{"className":18198},[941],[568,18200,18202],{"className":18201},[885],[568,18203,18205],{"className":18204,"style":4245},[889],[568,18206],{},[568,18208,6777],{"className":18209},[6809],[568,18211],{"className":18212,"style":6813},[647],[568,18214,18216,18219],{"className":18215},[641],[568,18217,8424],{"className":18218,"style":8459},[641,642],[568,18220,18222],{"className":18221},[4197],[568,18223,18225,18245],{"className":18224},[880,881],[568,18226,18228,18242],{"className":18227},[885],[568,18229,18231],{"className":18230,"style":10008},[889],[568,18232,18233,18236],{"style":8475},[568,18234],{"className":18235,"style":4214},[897],[568,18237,18239],{"className":18238},[902,903,904,905],[568,18240,324],{"className":18241},[641,905],[568,18243,942],{"className":18244},[941],[568,18246,18248],{"className":18247},[885],[568,18249,18251],{"className":18250,"style":4245},[889],[568,18252],{},[568,18254,6777],{"className":18255},[6809],[568,18257],{"className":18258,"style":6813},[647],[568,18260,18262,18265],{"className":18261},[641],[568,18263,8424],{"className":18264,"style":8459},[641,642],[568,18266,18268],{"className":18267},[4197],[568,18269,18271,18291],{"className":18270},[880,881],[568,18272,18274,18288],{"className":18273},[885],[568,18275,18277],{"className":18276,"style":10008},[889],[568,18278,18279,18282],{"style":8475},[568,18280],{"className":18281,"style":4214},[897],[568,18283,18285],{"className":18284},[902,903,904,905],[568,18286,268],{"className":18287},[641,905],[568,18289,942],{"className":18290},[941],[568,18292,18294],{"className":18293},[885],[568,18295,18297],{"className":18296,"style":4245},[889],[568,18298],{},[568,18300,6777],{"className":18301},[6809],[568,18303],{"className":18304,"style":6813},[647],[568,18306,18308,18311],{"className":18307},[641],[568,18309,8424],{"className":18310,"style":8459},[641,642],[568,18312,18314],{"className":18313},[4197],[568,18315,18317,18340],{"className":18316},[880,881],[568,18318,18320,18337],{"className":18319},[885],[568,18321,18323],{"className":18322,"style":10008},[889],[568,18324,18325,18328],{"style":8475},[568,18326],{"className":18327,"style":4214},[897],[568,18329,18331],{"className":18330},[902,903,904,905],[568,18332,18334],{"className":18333},[641,905],[568,18335,3694],{"className":18336},[641,905],[568,18338,942],{"className":18339},[941],[568,18341,18343],{"className":18342},[885],[568,18344,18346],{"className":18345,"style":4245},[889],[568,18347],{},[568,18349,6777],{"className":18350},[6809],[568,18352],{"className":18353,"style":6813},[647],[568,18355,18357,18360],{"className":18356},[641],[568,18358,8424],{"className":18359,"style":8459},[641,642],[568,18361,18363],{"className":18362},[4197],[568,18364,18366,18386],{"className":18365},[880,881],[568,18367,18369,18383],{"className":18368},[885],[568,18370,18372],{"className":18371,"style":10008},[889],[568,18373,18374,18377],{"style":8475},[568,18375],{"className":18376,"style":4214},[897],[568,18378,18380],{"className":18379},[902,903,904,905],[568,18381,735],{"className":18382},[641,905],[568,18384,942],{"className":18385},[941],[568,18387,18389],{"className":18388},[885],[568,18390,18392],{"className":18391,"style":4245},[889],[568,18393],{},[568,18395,6777],{"className":18396},[6809],[568,18398],{"className":18399,"style":6813},[647],[568,18401,18403,18406],{"className":18402},[641],[568,18404,8424],{"className":18405,"style":8459},[641,642],[568,18407,18409],{"className":18408},[4197],[568,18410,18412,18432],{"className":18411},[880,881],[568,18413,18415,18429],{"className":18414},[885],[568,18416,18418],{"className":18417,"style":10008},[889],[568,18419,18420,18423],{"style":8475},[568,18421],{"className":18422,"style":4214},[897],[568,18424,18426],{"className":18425},[902,903,904,905],[568,18427,343],{"className":18428},[641,905],[568,18430,942],{"className":18431},[941],[568,18433,18435],{"className":18434},[885],[568,18436,18438],{"className":18437,"style":4245},[889],[568,18439],{},[568,18441,6777],{"className":18442},[6809],[568,18444],{"className":18445,"style":6813},[647],[568,18447,18449,18452],{"className":18448},[641],[568,18450,8424],{"className":18451,"style":8459},[641,642],[568,18453,18455],{"className":18454},[4197],[568,18456,18458,18478],{"className":18457},[880,881],[568,18459,18461,18475],{"className":18460},[885],[568,18462,18464],{"className":18463,"style":10008},[889],[568,18465,18466,18469],{"style":8475},[568,18467],{"className":18468,"style":4214},[897],[568,18470,18472],{"className":18471},[902,903,904,905],[568,18473,287],{"className":18474},[641,905],[568,18476,942],{"className":18477},[941],[568,18479,18481],{"className":18480},[885],[568,18482,18484],{"className":18483,"style":4245},[889],[568,18485],{},[568,18487,6777],{"className":18488},[6809],[568,18490],{"className":18491,"style":6813},[647],[568,18493,18495,18498],{"className":18494},[641],[568,18496,8424],{"className":18497,"style":8459},[641,642],[568,18499,18501],{"className":18500},[4197],[568,18502,18504,18527],{"className":18503},[880,881],[568,18505,18507,18524],{"className":18506},[885],[568,18508,18510],{"className":18509,"style":10008},[889],[568,18511,18512,18515],{"style":8475},[568,18513],{"className":18514,"style":4214},[897],[568,18516,18518],{"className":18517},[902,903,904,905],[568,18519,18521],{"className":18520},[641,905],[568,18522,15907],{"className":18523},[641,905],[568,18525,942],{"className":18526},[941],[568,18528,18530],{"className":18529},[885],[568,18531,18533],{"className":18532,"style":4245},[889],[568,18534],{},[568,18536,6777],{"className":18537},[6809],[568,18539],{"className":18540,"style":6813},[647],[568,18542,18544,18547],{"className":18543},[641],[568,18545,8424],{"className":18546,"style":8459},[641,642],[568,18548,18550],{"className":18549},[4197],[568,18551,18553,18576],{"className":18552},[880,881],[568,18554,18556,18573],{"className":18555},[885],[568,18557,18559],{"className":18558,"style":10008},[889],[568,18560,18561,18564],{"style":8475},[568,18562],{"className":18563,"style":4214},[897],[568,18565,18567],{"className":18566},[902,903,904,905],[568,18568,18570],{"className":18569},[641,905],[568,18571,330],{"className":18572},[641,905],[568,18574,942],{"className":18575},[941],[568,18577,18579],{"className":18578},[885],[568,18580,18582],{"className":18581,"style":4245},[889],[568,18583],{},[568,18585,6777],{"className":18586},[6809],[568,18588],{"className":18589,"style":6813},[647],[568,18591,18593,18596],{"className":18592},[641],[568,18594,8424],{"className":18595,"style":8459},[641,642],[568,18597,18599],{"className":18598},[4197],[568,18600,18602,18622],{"className":18601},[880,881],[568,18603,18605,18619],{"className":18604},[885],[568,18606,18608],{"className":18607,"style":10008},[889],[568,18609,18610,18613],{"style":8475},[568,18611],{"className":18612,"style":4214},[897],[568,18614,18616],{"className":18615},[902,903,904,905],[568,18617,4050],{"className":18618},[641,905],[568,18620,942],{"className":18621},[941],[568,18623,18625],{"className":18624},[885],[568,18626,18628],{"className":18627,"style":4245},[889],[568,18629],{},[568,18631,6777],{"className":18632},[6809],[568,18634],{"className":18635,"style":6813},[647],[568,18637,18639,18642],{"className":18638},[641],[568,18640,8424],{"className":18641,"style":8459},[641,642],[568,18643,18645],{"className":18644},[4197],[568,18646,18648,18668],{"className":18647},[880,881],[568,18649,18651,18665],{"className":18650},[885],[568,18652,18654],{"className":18653,"style":10008},[889],[568,18655,18656,18659],{"style":8475},[568,18657],{"className":18658,"style":4214},[897],[568,18660,18662],{"className":18661},[902,903,904,905],[568,18663,306],{"className":18664},[641,905],[568,18666,942],{"className":18667},[941],[568,18669,18671],{"className":18670},[885],[568,18672,18674],{"className":18673,"style":4245},[889],[568,18675],{},[33,18677,18678,18681,18682,18751,18752,18821,18822,18979,18980,19078,19079,19151,19152,17441,19363,1491,19366,16127],{},[563,18679,18680],{},"优化后的总时间计算：","\n从 ",[568,18683,18685,18702],{"className":18684},[571],[568,18686,18688],{"className":18687},[575],[577,18689,18690],{"xmlns":579},[581,18691,18692,18700],{},[584,18693,18694],{},[4138,18695,18696,18698],{},[587,18697,8424],{},[595,18699,249],{},[620,18701,16266],{"encoding":622},[568,18703,18705],{"className":18704,"ariaHidden":628},[627],[568,18706,18708,18711],{"className":18707},[632],[568,18709],{"className":18710,"style":4187},[636],[568,18712,18714,18717],{"className":18713},[641],[568,18715,8424],{"className":18716,"style":8459},[641,642],[568,18718,18720],{"className":18719},[4197],[568,18721,18723,18743],{"className":18722},[880,881],[568,18724,18726,18740],{"className":18725},[885],[568,18727,18729],{"className":18728,"style":10008},[889],[568,18730,18731,18734],{"style":8475},[568,18732],{"className":18733,"style":4214},[897],[568,18735,18737],{"className":18736},[902,903,904,905],[568,18738,249],{"className":18739},[641,905],[568,18741,942],{"className":18742},[941],[568,18744,18746],{"className":18745},[885],[568,18747,18749],{"className":18748,"style":4245},[889],[568,18750],{}," 的开头 到 ",[568,18753,18755,18772],{"className":18754},[571],[568,18756,18758],{"className":18757},[575],[577,18759,18760],{"xmlns":579},[581,18761,18762,18770],{},[584,18763,18764],{},[4138,18765,18766,18768],{},[587,18767,8424],{},[595,18769,268],{},[620,18771,16684],{"encoding":622},[568,18773,18775],{"className":18774,"ariaHidden":628},[627],[568,18776,18778,18781],{"className":18777},[632],[568,18779],{"className":18780,"style":4187},[636],[568,18782,18784,18787],{"className":18783},[641],[568,18785,8424],{"className":18786,"style":8459},[641,642],[568,18788,18790],{"className":18789},[4197],[568,18791,18793,18813],{"className":18792},[880,881],[568,18794,18796,18810],{"className":18795},[885],[568,18797,18799],{"className":18798,"style":10008},[889],[568,18800,18801,18804],{"style":8475},[568,18802],{"className":18803,"style":4214},[897],[568,18805,18807],{"className":18806},[902,903,904,905],[568,18808,268],{"className":18809},[641,905],[568,18811,942],{"className":18812},[941],[568,18814,18816],{"className":18815},[885],[568,18817,18819],{"className":18818,"style":4245},[889],[568,18820],{}," 的开头（间隔 4 块），磁盘转动的时间是固定的：",[568,18823,18825,18860],{"className":18824},[571],[568,18826,18828],{"className":18827},[575],[577,18829,18830],{"xmlns":579},[581,18831,18832,18857],{},[584,18833,18834,18836,18838,18840,18842,18844,18846,18848,18850],{},[595,18835,306],{},[591,18837,1221],{},[591,18839,1062],{"stretchy":1061},[595,18841,274],{},[587,18843,607],{"mathvariant":606},[595,18845,15907],{},[591,18847,1071],{"stretchy":1061},[591,18849,593],{},[843,18851,18852,18855],{},[595,18853,18854],{},"120",[595,18856,15907],{},[620,18858,18859],{"encoding":622},"4 \\times (30\u002F13) = \\frac{120}{13}",[568,18861,18863,18881,18905],{"className":18862,"ariaHidden":628},[627],[568,18864,18866,18869,18872,18875,18878],{"className":18865},[632],[568,18867],{"className":18868,"style":1249},[636],[568,18870,306],{"className":18871},[641],[568,18873],{"className":18874,"style":1256},[647],[568,18876,1221],{"className":18877},[1260],[568,18879],{"className":18880,"style":1256},[647],[568,18882,18884,18887,18890,18893,18896,18899,18902],{"className":18883},[632],[568,18885],{"className":18886,"style":662},[636],[568,18888,1062],{"className":18889},[872],[568,18891,16108],{"className":18892},[641],[568,18894,1071],{"className":18895},[955],[568,18897],{"className":18898,"style":648},[647],[568,18900,593],{"className":18901},[652],[568,18903],{"className":18904,"style":648},[647],[568,18906,18908,18911],{"className":18907},[632],[568,18909],{"className":18910,"style":865},[636],[568,18912,18914,18917,18976],{"className":18913},[641],[568,18915],{"className":18916},[872,873],[568,18918,18920],{"className":18919},[843],[568,18921,18923,18968],{"className":18922},[880,881],[568,18924,18926,18965],{"className":18925},[885],[568,18927,18929,18943,18951],{"className":18928,"style":890},[889],[568,18930,18931,18934],{"style":893},[568,18932],{"className":18933,"style":898},[897],[568,18935,18937],{"className":18936},[902,903,904,905],[568,18938,18940],{"className":18939},[641,905],[568,18941,15907],{"className":18942},[641,905],[568,18944,18945,18948],{"style":914},[568,18946],{"className":18947,"style":898},[897],[568,18949],{"className":18950,"style":922},[921],[568,18952,18953,18956],{"style":925},[568,18954],{"className":18955,"style":898},[897],[568,18957,18959],{"className":18958},[902,903,904,905],[568,18960,18962],{"className":18961},[641,905],[568,18963,18854],{"className":18964},[641,905],[568,18966,942],{"className":18967},[941],[568,18969,18971],{"className":18970},[885],[568,18972,18974],{"className":18973,"style":949},[889],[568,18975],{},[568,18977],{"className":18978},[955,873]," ms。\n前 12 个记录，每次读取间隔精确为 ",[568,18981,18983,19001],{"className":18982},[571],[568,18984,18986],{"className":18985},[575],[577,18987,18988],{"xmlns":579},[581,18989,18990,18998],{},[584,18991,18992],{},[843,18993,18994,18996],{},[595,18995,18854],{},[595,18997,15907],{},[620,18999,19000],{"encoding":622},"\\frac{120}{13}",[568,19002,19004],{"className":19003,"ariaHidden":628},[627],[568,19005,19007,19010],{"className":19006},[632],[568,19008],{"className":19009,"style":865},[636],[568,19011,19013,19016,19075],{"className":19012},[641],[568,19014],{"className":19015},[872,873],[568,19017,19019],{"className":19018},[843],[568,19020,19022,19067],{"className":19021},[880,881],[568,19023,19025,19064],{"className":19024},[885],[568,19026,19028,19042,19050],{"className":19027,"style":890},[889],[568,19029,19030,19033],{"style":893},[568,19031],{"className":19032,"style":898},[897],[568,19034,19036],{"className":19035},[902,903,904,905],[568,19037,19039],{"className":19038},[641,905],[568,19040,15907],{"className":19041},[641,905],[568,19043,19044,19047],{"style":914},[568,19045],{"className":19046,"style":898},[897],[568,19048],{"className":19049,"style":922},[921],[568,19051,19052,19055],{"style":925},[568,19053],{"className":19054,"style":898},[897],[568,19056,19058],{"className":19057},[902,903,904,905],[568,19059,19061],{"className":19060},[641,905],[568,19062,18854],{"className":19063},[641,905],[568,19065,942],{"className":19066},[941],[568,19068,19070],{"className":19069},[885],[568,19071,19073],{"className":19072,"style":949},[889],[568,19074],{},[568,19076],{"className":19077},[955,873]," ms。\n最后一个记录 ",[568,19080,19082,19099],{"className":19081},[571],[568,19083,19085],{"className":19084},[575],[577,19086,19087],{"xmlns":579},[581,19088,19089,19097],{},[584,19090,19091],{},[4138,19092,19093,19095],{},[587,19094,8424],{},[595,19096,15907],{},[620,19098,17241],{"encoding":622},[568,19100,19102],{"className":19101,"ariaHidden":628},[627],[568,19103,19105,19108],{"className":19104},[632],[568,19106],{"className":19107,"style":4187},[636],[568,19109,19111,19114],{"className":19110},[641],[568,19112,8424],{"className":19113,"style":8459},[641,642],[568,19115,19117],{"className":19116},[4197],[568,19118,19120,19143],{"className":19119},[880,881],[568,19121,19123,19140],{"className":19122},[885],[568,19124,19126],{"className":19125,"style":10008},[889],[568,19127,19128,19131],{"style":8475},[568,19129],{"className":19130,"style":4214},[897],[568,19132,19134],{"className":19133},[902,903,904,905],[568,19135,19137],{"className":19136},[641,905],[568,19138,15907],{"className":19139},[641,905],[568,19141,942],{"className":19142},[941],[568,19144,19146],{"className":19145},[885],[568,19147,19149],{"className":19148,"style":4245},[889],[568,19150],{}," 只需读取并处理，耗时 ",[568,19153,19155,19185],{"className":19154},[571],[568,19156,19158],{"className":19157},[575],[577,19159,19160],{"xmlns":579},[581,19161,19162,19182],{},[584,19163,19164,19170,19172,19174,19176],{},[843,19165,19166,19168],{},[595,19167,274],{},[595,19169,15907],{},[591,19171,1508],{},[595,19173,324],{},[591,19175,593],{},[843,19177,19178,19180],{},[595,19179,8715],{},[595,19181,15907],{},[620,19183,19184],{"encoding":622},"\\frac{30}{13} + 5 = \\frac{95}{13}",[568,19186,19188,19271,19289],{"className":19187,"ariaHidden":628},[627],[568,19189,19191,19194,19262,19265,19268],{"className":19190},[632],[568,19192],{"className":19193,"style":865},[636],[568,19195,19197,19200,19259],{"className":19196},[641],[568,19198],{"className":19199},[872,873],[568,19201,19203],{"className":19202},[843],[568,19204,19206,19251],{"className":19205},[880,881],[568,19207,19209,19248],{"className":19208},[885],[568,19210,19212,19226,19234],{"className":19211,"style":890},[889],[568,19213,19214,19217],{"style":893},[568,19215],{"className":19216,"style":898},[897],[568,19218,19220],{"className":19219},[902,903,904,905],[568,19221,19223],{"className":19222},[641,905],[568,19224,15907],{"className":19225},[641,905],[568,19227,19228,19231],{"style":914},[568,19229],{"className":19230,"style":898},[897],[568,19232],{"className":19233,"style":922},[921],[568,19235,19236,19239],{"style":925},[568,19237],{"className":19238,"style":898},[897],[568,19240,19242],{"className":19241},[902,903,904,905],[568,19243,19245],{"className":19244},[641,905],[568,19246,274],{"className":19247},[641,905],[568,19249,942],{"className":19250},[941],[568,19252,19254],{"className":19253},[885],[568,19255,19257],{"className":19256,"style":949},[889],[568,19258],{},[568,19260],{"className":19261},[955,873],[568,19263],{"className":19264,"style":1256},[647],[568,19266,1508],{"className":19267},[1260],[568,19269],{"className":19270,"style":1256},[647],[568,19272,19274,19277,19280,19283,19286],{"className":19273},[632],[568,19275],{"className":19276,"style":691},[636],[568,19278,324],{"className":19279},[641],[568,19281],{"className":19282,"style":648},[647],[568,19284,593],{"className":19285},[652],[568,19287],{"className":19288,"style":648},[647],[568,19290,19292,19295],{"className":19291},[632],[568,19293],{"className":19294,"style":865},[636],[568,19296,19298,19301,19360],{"className":19297},[641],[568,19299],{"className":19300},[872,873],[568,19302,19304],{"className":19303},[843],[568,19305,19307,19352],{"className":19306},[880,881],[568,19308,19310,19349],{"className":19309},[885],[568,19311,19313,19327,19335],{"className":19312,"style":890},[889],[568,19314,19315,19318],{"style":893},[568,19316],{"className":19317,"style":898},[897],[568,19319,19321],{"className":19320},[902,903,904,905],[568,19322,19324],{"className":19323},[641,905],[568,19325,15907],{"className":19326},[641,905],[568,19328,19329,19332],{"style":914},[568,19330],{"className":19331,"style":898},[897],[568,19333],{"className":19334,"style":922},[921],[568,19336,19337,19340],{"style":925},[568,19338],{"className":19339,"style":898},[897],[568,19341,19343],{"className":19342},[902,903,904,905],[568,19344,19346],{"className":19345},[641,905],[568,19347,8715],{"className":19348},[641,905],[568,19350,942],{"className":19351},[941],[568,19353,19355],{"className":19354},[885],[568,19356,19358],{"className":19357,"style":949},[889],[568,19359],{},[568,19361],{"className":19362},[955,873],[563,19364,19365],{},"优化后的总时间",[568,19367,19369,19417],{"className":19368},[571],[568,19370,19372],{"className":19371},[575],[577,19373,19374],{"xmlns":579},[581,19375,19376,19414],{},[584,19377,19378,19380,19382,19384,19390,19392,19394,19400,19402,19409,19411],{},[595,19379,3694],{},[591,19381,1221],{},[591,19383,1062],{"stretchy":1061},[843,19385,19386,19388],{},[595,19387,18854],{},[595,19389,15907],{},[591,19391,1071],{"stretchy":1061},[591,19393,1508],{},[843,19395,19396,19398],{},[595,19397,8715],{},[595,19399,15907],{},[591,19401,593],{},[843,19403,19404,19407],{},[595,19405,19406],{},"1535",[595,19408,15907],{},[591,19410,738],{},[595,19412,19413],{"mathvariant":2397},"118.08",[620,19415,19416],{"encoding":622},"12 \\times (\\frac{120}{13}) + \\frac{95}{13} = \\frac{1535}{13} \\approx \\mathbf{118.08}",[568,19418,19420,19438,19527,19610,19693],{"className":19419,"ariaHidden":628},[627],[568,19421,19423,19426,19429,19432,19435],{"className":19422},[632],[568,19424],{"className":19425,"style":1249},[636],[568,19427,3694],{"className":19428},[641],[568,19430],{"className":19431,"style":1256},[647],[568,19433,1221],{"className":19434},[1260],[568,19436],{"className":19437,"style":1256},[647],[568,19439,19441,19444,19447,19515,19518,19521,19524],{"className":19440},[632],[568,19442],{"className":19443,"style":865},[636],[568,19445,1062],{"className":19446},[872],[568,19448,19450,19453,19512],{"className":19449},[641],[568,19451],{"className":19452},[872,873],[568,19454,19456],{"className":19455},[843],[568,19457,19459,19504],{"className":19458},[880,881],[568,19460,19462,19501],{"className":19461},[885],[568,19463,19465,19479,19487],{"className":19464,"style":890},[889],[568,19466,19467,19470],{"style":893},[568,19468],{"className":19469,"style":898},[897],[568,19471,19473],{"className":19472},[902,903,904,905],[568,19474,19476],{"className":19475},[641,905],[568,19477,15907],{"className":19478},[641,905],[568,19480,19481,19484],{"style":914},[568,19482],{"className":19483,"style":898},[897],[568,19485],{"className":19486,"style":922},[921],[568,19488,19489,19492],{"style":925},[568,19490],{"className":19491,"style":898},[897],[568,19493,19495],{"className":19494},[902,903,904,905],[568,19496,19498],{"className":19497},[641,905],[568,19499,18854],{"className":19500},[641,905],[568,19502,942],{"className":19503},[941],[568,19505,19507],{"className":19506},[885],[568,19508,19510],{"className":19509,"style":949},[889],[568,19511],{},[568,19513],{"className":19514},[955,873],[568,19516,1071],{"className":19517},[955],[568,19519],{"className":19520,"style":1256},[647],[568,19522,1508],{"className":19523},[1260],[568,19525],{"className":19526,"style":1256},[647],[568,19528,19530,19533,19601,19604,19607],{"className":19529},[632],[568,19531],{"className":19532,"style":865},[636],[568,19534,19536,19539,19598],{"className":19535},[641],[568,19537],{"className":19538},[872,873],[568,19540,19542],{"className":19541},[843],[568,19543,19545,19590],{"className":19544},[880,881],[568,19546,19548,19587],{"className":19547},[885],[568,19549,19551,19565,19573],{"className":19550,"style":890},[889],[568,19552,19553,19556],{"style":893},[568,19554],{"className":19555,"style":898},[897],[568,19557,19559],{"className":19558},[902,903,904,905],[568,19560,19562],{"className":19561},[641,905],[568,19563,15907],{"className":19564},[641,905],[568,19566,19567,19570],{"style":914},[568,19568],{"className":19569,"style":898},[897],[568,19571],{"className":19572,"style":922},[921],[568,19574,19575,19578],{"style":925},[568,19576],{"className":19577,"style":898},[897],[568,19579,19581],{"className":19580},[902,903,904,905],[568,19582,19584],{"className":19583},[641,905],[568,19585,8715],{"className":19586},[641,905],[568,19588,942],{"className":19589},[941],[568,19591,19593],{"className":19592},[885],[568,19594,19596],{"className":19595,"style":949},[889],[568,19597],{},[568,19599],{"className":19600},[955,873],[568,19602],{"className":19603,"style":648},[647],[568,19605,593],{"className":19606},[652],[568,19608],{"className":19609,"style":648},[647],[568,19611,19613,19616,19684,19687,19690],{"className":19612},[632],[568,19614],{"className":19615,"style":865},[636],[568,19617,19619,19622,19681],{"className":19618},[641],[568,19620],{"className":19621},[872,873],[568,19623,19625],{"className":19624},[843],[568,19626,19628,19673],{"className":19627},[880,881],[568,19629,19631,19670],{"className":19630},[885],[568,19632,19634,19648,19656],{"className":19633,"style":890},[889],[568,19635,19636,19639],{"style":893},[568,19637],{"className":19638,"style":898},[897],[568,19640,19642],{"className":19641},[902,903,904,905],[568,19643,19645],{"className":19644},[641,905],[568,19646,15907],{"className":19647},[641,905],[568,19649,19650,19653],{"style":914},[568,19651],{"className":19652,"style":898},[897],[568,19654],{"className":19655,"style":922},[921],[568,19657,19658,19661],{"style":925},[568,19659],{"className":19660,"style":898},[897],[568,19662,19664],{"className":19663},[902,903,904,905],[568,19665,19667],{"className":19666},[641,905],[568,19668,19406],{"className":19669},[641,905],[568,19671,942],{"className":19672},[941],[568,19674,19676],{"className":19675},[885],[568,19677,19679],{"className":19678,"style":949},[889],[568,19680],{},[568,19682],{"className":19683},[955,873],[568,19685],{"className":19686,"style":648},[647],[568,19688,738],{"className":19689},[652],[568,19691],{"className":19692,"style":648},[647],[568,19694,19696,19699],{"className":19695},[632],[568,19697],{"className":19698,"style":691},[636],[568,19700,19702],{"className":19701},[641],[568,19703,19413],{"className":19704},[641,2676],[554,19706,15860],{"id":19707},"常见易错点-common-pitfalls-1",[26,19709,19710,19711,19744,19745,19748,19749,19797],{},"在计算优化后的总时间时，学生容易错误地直接把\"等待时间归零\"来计算单步时间。实际上，由于处理时间 (5ms) 并没有刚好踩准物理块的边界，磁头到达第 5 块之前依然有非常短暂的等待对齐时间（本题为 ",[568,19712,19714,19732],{"className":19713},[571],[568,19715,19717],{"className":19716},[575],[577,19718,19719],{"xmlns":579},[581,19720,19721,19729],{},[584,19722,19723,19725,19727],{},[595,19724,7470],{},[587,19726,607],{"mathvariant":606},[595,19728,15907],{},[620,19730,19731],{"encoding":622},"25\u002F13",[568,19733,19735],{"className":19734,"ariaHidden":628},[627],[568,19736,19738,19741],{"className":19737},[632],[568,19739],{"className":19740,"style":662},[636],[568,19742,19731],{"className":19743},[641]," ms）。最稳妥的计算方式是直接看两个记录",[563,19746,19747],{},"开头之间的物理距离","（4 块的旋转时间 ",[568,19750,19752,19772],{"className":19751},[571],[568,19753,19755],{"className":19754},[575],[577,19756,19757],{"xmlns":579},[581,19758,19759,19769],{},[584,19760,19761,19763,19765,19767],{},[591,19762,593],{},[595,19764,18854],{},[587,19766,607],{"mathvariant":606},[595,19768,15907],{},[620,19770,19771],{"encoding":622},"= 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