共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.空白处(23)应选择()
A. reset
B. acknowledgment
C. sequence
D. synchroizer
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共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.空白处(22)应选择()
A. give-up
B. abandon
C. quit
D. connection
设关系模式R,其中U={A,B,C,D,E},F={A→BC,C→D,BC→E,E→A},则分解p={R1(ABCE),R2(CD)}满足()
A. 具有无损连接性、保持函数依赖
B. 不具有无损连接性、保持函数依赖
C. 具有无损连接性、不保持函数依赖
D. 不具有无损连接性、不保持函数依赖
通常将"C:\Windows\myprogram.exe"文件设置成只读和隐藏属性,以便控制用户对该文件的访问,这一级安全管理称为()安全管理。
A. 文件级
B. 目录级
C. 用户级
D. 系统级
在操作系统的虚拟内存管理中,内存地址由页目录号、页号和页内偏移3个部分组成。如果页目录号占10位、页号占10位、页内偏移占12位,那么()
A. 页大小是1K,一个页目录最多4K页
B. 页大小是2K,一个页目录最多2K页
C. 页大小是2K,一个页目录最多1K页
D. 页大小是4K,一个页目录最多1K页