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临界区就是临界资源所在的区域。
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对临界区的正确论述是 ①临界区是指进程中实现进程互斥的那段代码 ②临界区是指进程中用于实现进程同步
①，②
①，②，⑤
⑤，⑥
①，②，③，④，⑤，⑥
下列关于临界区和临界资源的说法正确的有Ⅰ．银行家算法可以用来解决临界区CriticalSection
Ⅰ、Ⅱ
Ⅰ、Ⅳ
只有Ⅲ
以上答案都错误
临界资源的概念是①而临界区是指②
为了保证临界资源的正确使用进程在结束对临界资源的访问后必须通过下列哪一区才能离开
进入区
临界区
退出区
剩余区
下列对临界区的论述中正确的是
临界区是指进程中用于实现进程互斥的那段代码。
临界区是指进程中用于实现进程同步的那段代码。
临界区是指进程中用于实现共享资源的那段代码。
临界区是指进程中访问临界资源的那段代码。
临界区是指______
一组临界资源的集合
可共享的一块内存区
访问临界资源的一段代码
请求访问临界资源的代码
什么是临界资源和临界区
临界资源的概念是______而临界区是______
临界资源是指________而临界区是指________
下列关于临界区叙述正确的是
进程中访问临界资源的那段程序称为临界区
临界区最多允许两个进程进入
进程进入临界区的要求可以在无限的时间内得到满足
系统中一些资源一次只允许有限的进程使用，称之为临界资源
对临界区的正确论述是①临界区是指进程中实现进程互斥的那段代码②临界区是指进程中用于实现进程同步的那段
①，②
①，②，⑤
⑤，⑥
①，②，⑧，④，⑤，⑥
对进程间互斥的使用临界资源进程可以
互斥的进入临界区
互斥的进入各自的临界区
互斥的进入同一临界区
互斥的进入各自的同类资源临界区
什么是临界资源什么是临界区
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某操作系统将消息缓冲通信作为进程之间通信的基本手段Send和Receive分别为发送消息和接收消息原语请设计一种方案用于Send和Receive原语来实现基于信号量的PV操作
简述计算机系统的中断机制及其作用中断装置如何判别发生的是自愿性中断还是强迫性中断
Directions: Achemicalplantshouldberesponsibleforthewaterpollutioninanearbyriver.WritealettertotheCityEnvironmentProtectionAgencyto 注投诉信是应用文命题的重点之一 1statethepresentsituation 2suggestwaystodealwiththeproblemand 3expressyoursincerehope.Youshouldwriteabout100wordsonANSWERSHEET2. Donotsignyourownnameattheendoftheletter.Use"LiMing"instead. Donotneedtowritetheaddress.
PrinceKlemensVonMetternichforeignministeroftheAustrianEmpireduringtheNapoleoniceraanditsaftermathwouldhavenotroublerecognizingGoogle.Tohimtheworld’smostpopularweb-searchenginewouldcloselyresembletheNapoleonicFrancethatinhisyouthhumiliatedAustriaandEurope’sotherpowers.Itsrivals—Yahoo!thelargestofthetraditionalwebgatewayseBaythebiggestonlineauctionandtradingsiteandMicrosoftasoftwareempirethatownsMSNastrugglingwebportal—wouldlookalotlikeRussiaPrussiaandAustria.Metternichrespondedbyforginganallianceamongthosethreemonarchiestocreatea"balanceofpower"againstFrance.Google’senemieshemightsayoughtnowtodothesamething. GoogleannouncedtwonewconquestsonAugust7th.ItstruckadealwithViacoman"old"mediafirmunderwhichitwillsyndicatevideoclipsfromViacombrandssuchasMTVandNickelodeontootherwebsitesandintegrateadvertisementsintothem.ThismakesGoogletheclearleaderinthefledglingbutpromisingmarketforweb-videoadvertising.ItalsoannouncedadealwithNewsCorporationanothermediagiantunderwhichitwillpro-videallthesearchandtext-advertisingtechnologyonNewsCorporation’swebsitesincludingMySpaceanenormouslypopularsocial-networkingsite. ThesearehardblowsforYahoo!andMSNwhichhadalsobeennegotiatingwithNewsCorporation.BothfirmshavebeenlosingmarketshareinwebsearchtoGoogleoverthepastyear—Googlenowhashalfthemarket.TheyhavealsofallenfurtherbehindintheiradvertisingtechnologiesandnetworkssothatbothmakelessmoneythanGoogledoesfromthesamenumberofsearches.SafaRashtchyananalystatPiperJaffrayasecuritiesfirmestimatesthatforeveryadvertisingdollarthatGooglemakesonasearchqueryYahoo!makesonly60-70cents.LastmonthYahoo!saidthatanewadvertisingalgorithmthatithaddesignedtoclosethegapinprofitabilitywillbedelayedanditssharepricefellby22%itsbiggest-everone-daydrop. MSNisfurtherbehindGooglethanYahoo!insearchanditsparentMicrosoftfacesanevenmorefundamentalthreatfromtheexpansionistnewpower.ManyofGoogle’snewventuresbeyondwebsearchenableuserstodothingsfreeofchargethroughtheirwebbrowsersthattheynowdousingMicrosoftsoftwareontheirpersonalcomputers.Googleoffersarudimentarybutfreeonlinewordprocessorandspreadsheetforinstance. ThesmallereBayontheotherhandmightinonesenseclaimGoogleasanally.Google’ssearchresultssendalotoftraffictoeBay’sauctionsiteandeBayisoneofthebiggestadvertisersonGoogle’snetwork.Buttherelationshipisimbalanced.Aninfluentialre-centstudyfromBerkeley’sHaasSchoolofBusinessestimatedthatabout12%ofeBay’srevenuescomeindirectlyfromGooglewhereasGooglegetsonly3%ofitsrevenuesfromeBay.WorstofallforeBayGoogleisstartingtoundercutitscorebusiness.SellersaresettinguptheirownwebsitesandbuyingtextadvertisementsfromGoogleandbuyersareusingitssearchratherthaneBaytoconnectwithsellersdirectly.Asaresult"eBaywouldbewisetostrikeadeeppartnershipwithYahoo!orMicrosoftinordertoregainabalanceofpowerintheindustry"saidthestudy’sauthorsJulienDecotandSteveLeesoundinglikediplomatsattheCongressofViennain1814. PrinceKlemensismentionedinthefirstparagraphto
PrinceKlemensVonMetternichforeignministeroftheAustrianEmpireduringtheNapoleoniceraanditsaftermathwouldhavenotroublerecognizingGoogle.Tohimtheworld’smostpopularweb-searchenginewouldcloselyresembletheNapoleonicFrancethatinhisyouthhumiliatedAustriaandEurope’sotherpowers.Itsrivals—Yahoo!thelargestofthetraditionalwebgatewayseBaythebiggestonlineauctionandtradingsiteandMicrosoftasoftwareempirethatownsMSNastrugglingwebportal—wouldlookalotlikeRussiaPrussiaandAustria.Metternichrespondedbyforginganallianceamongthosethreemonarchiestocreatea"balanceofpower"againstFrance.Google’senemieshemightsayoughtnowtodothesamething. GoogleannouncedtwonewconquestsonAugust7th.ItstruckadealwithViacoman"old"mediafirmunderwhichitwillsyndicatevideoclipsfromViacombrandssuchasMTVandNickelodeontootherwebsitesandintegrateadvertisementsintothem.ThismakesGoogletheclearleaderinthefledglingbutpromisingmarketforweb-videoadvertising.ItalsoannouncedadealwithNewsCorporationanothermediagiantunderwhichitwillpro-videallthesearchandtext-advertisingtechnologyonNewsCorporation’swebsitesincludingMySpaceanenormouslypopularsocial-networkingsite. ThesearehardblowsforYahoo!andMSNwhichhadalsobeennegotiatingwithNewsCorporation.BothfirmshavebeenlosingmarketshareinwebsearchtoGoogleoverthepastyear—Googlenowhashalfthemarket.TheyhavealsofallenfurtherbehindintheiradvertisingtechnologiesandnetworkssothatbothmakelessmoneythanGoogledoesfromthesamenumberofsearches.SafaRashtchyananalystatPiperJaffrayasecuritiesfirmestimatesthatforeveryadvertisingdollarthatGooglemakesonasearchqueryYahoo!makesonly60-70cents.LastmonthYahoo!saidthatanewadvertisingalgorithmthatithaddesignedtoclosethegapinprofitabilitywillbedelayedanditssharepricefellby22%itsbiggest-everone-daydrop. MSNisfurtherbehindGooglethanYahoo!insearchanditsparentMicrosoftfacesanevenmorefundamentalthreatfromtheexpansionistnewpower.ManyofGoogle’snewventuresbeyondwebsearchenableuserstodothingsfreeofchargethroughtheirwebbrowsersthattheynowdousingMicrosoftsoftwareontheirpersonalcomputers.Googleoffersarudimentarybutfreeonlinewordprocessorandspreadsheetforinstance. ThesmallereBayontheotherhandmightinonesenseclaimGoogleasanally.Google’ssearchresultssendalotoftraffictoeBay’sauctionsiteandeBayisoneofthebiggestadvertisersonGoogle’snetwork.Buttherelationshipisimbalanced.Aninfluentialre-centstudyfromBerkeley’sHaasSchoolofBusinessestimatedthatabout12%ofeBay’srevenuescomeindirectlyfromGooglewhereasGooglegetsonly3%ofitsrevenuesfromeBay.WorstofallforeBayGoogleisstartingtoundercutitscorebusiness.SellersaresettinguptheirownwebsitesandbuyingtextadvertisementsfromGoogleandbuyersareusingitssearchratherthaneBaytoconnectwithsellersdirectly.Asaresult"eBaywouldbewisetostrikeadeeppartnershipwithYahoo!orMicrosoftinordertoregainabalanceofpowerintheindustry"saidthestudy’sauthorsJulienDecotandSteveLeesoundinglikediplomatsattheCongressofViennain1814. Yahoo!andMSNaremakinglessmoneyforthesamenumberofsearcheschieflybecause
某个操作系统的设计目标是同时支持实时任务和交互式任务它的实现采用混合式多线程策略处理器调度策略采用多队列策略在系统资源匮乏时可以采用中级调度来平衡系统负载该操作系统中存在着哪些与处理器调度有关的实体
PrinceKlemensVonMetternichforeignministeroftheAustrianEmpireduringtheNapoleoniceraanditsaftermathwouldhavenotroublerecognizingGoogle.Tohimtheworld’smostpopularweb-searchenginewouldcloselyresembletheNapoleonicFrancethatinhisyouthhumiliatedAustriaandEurope’sotherpowers.Itsrivals—Yahoo!thelargestofthetraditionalwebgatewayseBaythebiggestonlineauctionandtradingsiteandMicrosoftasoftwareempirethatownsMSNastrugglingwebportal—wouldlookalotlikeRussiaPrussiaandAustria.Metternichrespondedbyforginganallianceamongthosethreemonarchiestocreatea"balanceofpower"againstFrance.Google’senemieshemightsayoughtnowtodothesamething. GoogleannouncedtwonewconquestsonAugust7th.ItstruckadealwithViacoman"old"mediafirmunderwhichitwillsyndicatevideoclipsfromViacombrandssuchasMTVandNickelodeontootherwebsitesandintegrateadvertisementsintothem.ThismakesGoogletheclearleaderinthefledglingbutpromisingmarketforweb-videoadvertising.ItalsoannouncedadealwithNewsCorporationanothermediagiantunderwhichitwillpro-videallthesearchandtext-advertisingtechnologyonNewsCorporation’swebsitesincludingMySpaceanenormouslypopularsocial-networkingsite. ThesearehardblowsforYahoo!andMSNwhichhadalsobeennegotiatingwithNewsCorporation.BothfirmshavebeenlosingmarketshareinwebsearchtoGoogleoverthepastyear—Googlenowhashalfthemarket.TheyhavealsofallenfurtherbehindintheiradvertisingtechnologiesandnetworkssothatbothmakelessmoneythanGoogledoesfromthesamenumberofsearches.SafaRashtchyananalystatPiperJaffrayasecuritiesfirmestimatesthatforeveryadvertisingdollarthatGooglemakesonasearchqueryYahoo!makesonly60-70cents.LastmonthYahoo!saidthatanewadvertisingalgorithmthatithaddesignedtoclosethegapinprofitabilitywillbedelayedanditssharepricefellby22%itsbiggest-everone-daydrop. MSNisfurtherbehindGooglethanYahoo!insearchanditsparentMicrosoftfacesanevenmorefundamentalthreatfromtheexpansionistnewpower.ManyofGoogle’snewventuresbeyondwebsearchenableuserstodothingsfreeofchargethroughtheirwebbrowsersthattheynowdousingMicrosoftsoftwareontheirpersonalcomputers.Googleoffersarudimentarybutfreeonlinewordprocessorandspreadsheetforinstance. ThesmallereBayontheotherhandmightinonesenseclaimGoogleasanally.Google’ssearchresultssendalotoftraffictoeBay’sauctionsiteandeBayisoneofthebiggestadvertisersonGoogle’snetwork.Buttherelationshipisimbalanced.Aninfluentialre-centstudyfromBerkeley’sHaasSchoolofBusinessestimatedthatabout12%ofeBay’srevenuescomeindirectlyfromGooglewhereasGooglegetsonly3%ofitsrevenuesfromeBay.WorstofallforeBayGoogleisstartingtoundercutitscorebusiness.SellersaresettinguptheirownwebsitesandbuyingtextadvertisementsfromGoogleandbuyersareusingitssearchratherthaneBaytoconnectwithsellersdirectly.Asaresult"eBaywouldbewisetostrikeadeeppartnershipwithYahoo!orMicrosoftinordertoregainabalanceofpowerintheindustry"saidthestudy’sauthorsJulienDecotandSteveLeesoundinglikediplomatsattheCongressofViennain1814. JulienandSteveseemtosuggestthat
管道通信的基本思想是什么UNIX操作系统在管道通信中是如何避免死锁的
[A]Convenientpackaging [B]Healthandwellness [C]Skepticalcustomers [D]Enormousmarkets [E]Soaringsales [F]Trendydrink Inthelast40yearsthebottledwaterindustryhasgonefromabusinessprospectthatfewtookseriouslytoaglobalindustryworthbillionsofpounds.Thecommodityitselfremainssimple.Thewaywethinkaboutithaschangedfundamentally.Waterisnaturalpureandsourcedatminimalcost.Itsrealvalueliesinitsmarketingandbranding."Ithinkbottledwateristhemostrevealingsubstanceforshowingushowtheglobalcapitalistmarketworkstoday"saysRichardWilkprofessorofanthropologyatIndianaUniversity."Inasensewe’rebuyingchoicewe’rebuyingfreedom.That’stheonlythingthatcanexplainwhyyouwouldpaymoneyforabottleofsomethingthatyoucanotherwisegetforfree." 41.______ Throughaconfectionofadvertisingandmarketingbottledwaterhasbecomeoneofthebiggestsuccessstoriesinthemodernfoodandbeverageindustry."Thedemandforbottlewaterhasgrownexponentiallyinthelastfewdecades"saysDr.PeterGleickauthorofBottledandSold."It’sdoubledit’sdoubledagainandit’sdoubledagain.Andthebottlewatercompaniesseeenormousmarketsnotjustintherichcountriesbutalsointhepoorercountries." Noactualvariety Somepeoplethinkthatbottledwateristhehighpointofglobalcapitalismparticularlythepeopleinthebottledwaterbusiness."Ithinkbottledwateractuallyrepresentsakindofcaricatureoftheglobaleconomy.Itprovidespeopleinthedevelopedworldwith20or30varietiesofsomethingforwhichthereisnoactualvariety"saysCharlesFishmanauthorofTheBigThirst. 42.______. Atthebeginningtherereallywasnovarietyandthebottledwaterphenomenonbeganwithonebrand.Perrier佩绿雅矿泉水品牌wasatriumphofadvertisingcreatingabrandthatwastodefineageneration.AttheheartofthecampaigntomakethebrandpopularwasRichardWheatleyoftheLeoBurnettadvertisingagencybetween1979and1994."Perrierpopularisedbottledwater"hesays."Itmadeitacceptablemorethanacceptableitmadeit...desirable."Butitwasnotaninstantsuccess.WhenPerrierUKwaslookingtoincreaseitssalesintheearly1970’sitfacedaskepticalpublic.Manyquestionedwhyanyonewouldbuywaterwhenyoucouldgetitfreefromthetap. 43.______. FacedwithobstaclesPerrierturnedtoadvertisingwithacampaignthatwastochangeourconsumerlandscapeforever.Thecampaignwasamarketingcoupandsaleswentthroughtherooffrom12millionbottlesin1980to152millionbytheendofthedecade.Perrierwasnolongerjustabottleofwater.Themarketingandadvertisingteamshadestablishedacrucialemotionallinkbetweentheproductandtheconsumers."Perrierbecameabadge"saysMichaelBellaschairmanoftheBeverageMarketingCorporation."WhenyouheldaPerrierbottleupitsaidsomethingaboutyourselfitsaidyouweresophisticatedyouunderstoodwhatwashappeningintheworld.Itwasaperfectbeveragefortheyoungandcomingbusinessexecutivesthetrend-setters." 44.______. Inanageofinstantgratificationstillwaterinportablebottlesprovidedwhatpeopleneededexactlywhentheyneededit."Peopleingeneralaremoreandmoretimepressed"saysMr.Fishman."Wedon’tcookourownmealsanymoreweeatpreparedfoodsofallkinds.Andthere’snothingmoreappealingthanabottleofcoldwateratamomentwhenyou’rereallythirsty.ButIthinkbottledwaterisoneofthoseproductsthatonmanyoccasionswhenpeoplebuyitwhatthey’rebuyingisn’tthewatersomuchasthebottle.Thatisthepackageandtheconvenienceatthatmoment." 45.______. WhenpeopleboughtthisconveniencewhattheywerereallybuyingwasPolyethyleneTerephthalateorPETthesinglemostimportantinnovationintheindustry’shistory.StrongshatterproofandahighlyvaluedformofpolyesterPETisaby-productoftheoilindustry.Itisnowutilisedinthepackagingofeverythingfrompharmaceuticalsandsoaptoreadymeals.InyearstocometheenvironmentalimpactofPETwouldhaunttheindustryandraisequestionsaboutitsverysurvivalbutinthe1990sthiswasarevolution.AccordingtoMr.Bellasitwasbehindthesubsequentincrediblegrowthoftheindustry."StartingwiththeintroductionofthesmallpremiumPETwatersthecategorystartedtoexplode"saysMr.Bellas."ThebottledwaterindustrybeforePETonthelistofallbeveragecategorieswasnumberseven.WiththeadventofPETwaterjumpedtothenumbertwospotbehindcarbonatedsoftdrinks." Bybrandingandmarketingwaterbottledwaterhasbeentransformedfromsomethingthatmanyofustookforgrantedintoaproductthatnowmakesbillionsforglobalmultinationalcompanies. 45
某分时系统中的进程可能出现如图2-13所示的状态变化回答下列问题 把图2-13中的每一个状态变化的原因填在表2-8相应的栏中
著名的哲学家就餐问题是指五位哲学家围圆桌就座桌上每二人之间放一根筷子任一位哲学家修学中饿了便可且只能拿起左右两边的筷子吃饭餐后将两根筷子各放回原处自己也继续做学问如此往复即对哲学家Pii=01234有循环进程SiPi做学问Pi取左手的i号筷子和右手的i+1rood5号筷子Pi就餐Pi将两根筷子分放回原处哲学家就餐问题是这样5个进程组成的系统请分别用死锁预防死锁避免死锁检测与恢复改造系统
消息缓冲通信技术是一种高级通信机制由Hansen首先提出请回答下列问题给出消息缓冲机制有限缓冲的基本工作原理
[A]Convenientpackaging [B]Healthandwellness [C]Skepticalcustomers [D]Enormousmarkets [E]Soaringsales [F]Trendydrink Inthelast40yearsthebottledwaterindustryhasgonefromabusinessprospectthatfewtookseriouslytoaglobalindustryworthbillionsofpounds.Thecommodityitselfremainssimple.Thewaywethinkaboutithaschangedfundamentally.Waterisnaturalpureandsourcedatminimalcost.Itsrealvalueliesinitsmarketingandbranding."Ithinkbottledwateristhemostrevealingsubstanceforshowingushowtheglobalcapitalistmarketworkstoday"saysRichardWilkprofessorofanthropologyatIndianaUniversity."Inasensewe’rebuyingchoicewe’rebuyingfreedom.That’stheonlythingthatcanexplainwhyyouwouldpaymoneyforabottleofsomethingthatyoucanotherwisegetforfree." 41.______ Throughaconfectionofadvertisingandmarketingbottledwaterhasbecomeoneofthebiggestsuccessstoriesinthemodernfoodandbeverageindustry."Thedemandforbottlewaterhasgrownexponentiallyinthelastfewdecades"saysDr.PeterGleickauthorofBottledandSold."It’sdoubledit’sdoubledagainandit’sdoubledagain.Andthebottlewatercompaniesseeenormousmarketsnotjustintherichcountriesbutalsointhepoorercountries." Noactualvariety Somepeoplethinkthatbottledwateristhehighpointofglobalcapitalismparticularlythepeopleinthebottledwaterbusiness."Ithinkbottledwateractuallyrepresentsakindofcaricatureoftheglobaleconomy.Itprovidespeopleinthedevelopedworldwith20or30varietiesofsomethingforwhichthereisnoactualvariety"saysCharlesFishmanauthorofTheBigThirst. 42.______. Atthebeginningtherereallywasnovarietyandthebottledwaterphenomenonbeganwithonebrand.Perrier佩绿雅矿泉水品牌wasatriumphofadvertisingcreatingabrandthatwastodefineageneration.AttheheartofthecampaigntomakethebrandpopularwasRichardWheatleyoftheLeoBurnettadvertisingagencybetween1979and1994."Perrierpopularisedbottledwater"hesays."Itmadeitacceptablemorethanacceptableitmadeit...desirable."Butitwasnotaninstantsuccess.WhenPerrierUKwaslookingtoincreaseitssalesintheearly1970’sitfacedaskepticalpublic.Manyquestionedwhyanyonewouldbuywaterwhenyoucouldgetitfreefromthetap. 43.______. FacedwithobstaclesPerrierturnedtoadvertisingwithacampaignthatwastochangeourconsumerlandscapeforever.Thecampaignwasamarketingcoupandsaleswentthroughtherooffrom12millionbottlesin1980to152millionbytheendofthedecade.Perrierwasnolongerjustabottleofwater.Themarketingandadvertisingteamshadestablishedacrucialemotionallinkbetweentheproductandtheconsumers."Perrierbecameabadge"saysMichaelBellaschairmanoftheBeverageMarketingCorporation."WhenyouheldaPerrierbottleupitsaidsomethingaboutyourselfitsaidyouweresophisticatedyouunderstoodwhatwashappeningintheworld.Itwasaperfectbeveragefortheyoungandcomingbusinessexecutivesthetrend-setters." 44.______. Inanageofinstantgratificationstillwaterinportablebottlesprovidedwhatpeopleneededexactlywhentheyneededit."Peopleingeneralaremoreandmoretimepressed"saysMr.Fishman."Wedon’tcookourownmealsanymoreweeatpreparedfoodsofallkinds.Andthere’snothingmoreappealingthanabottleofcoldwateratamomentwhenyou’rereallythirsty.ButIthinkbottledwaterisoneofthoseproductsthatonmanyoccasionswhenpeoplebuyitwhatthey’rebuyingisn’tthewatersomuchasthebottle.Thatisthepackageandtheconvenienceatthatmoment." 45.______. WhenpeopleboughtthisconveniencewhattheywerereallybuyingwasPolyethyleneTerephthalateorPETthesinglemostimportantinnovationintheindustry’shistory.StrongshatterproofandahighlyvaluedformofpolyesterPETisaby-productoftheoilindustry.Itisnowutilisedinthepackagingofeverythingfrompharmaceuticalsandsoaptoreadymeals.InyearstocometheenvironmentalimpactofPETwouldhaunttheindustryandraisequestionsaboutitsverysurvivalbutinthe1990sthiswasarevolution.AccordingtoMr.Bellasitwasbehindthesubsequentincrediblegrowthoftheindustry."StartingwiththeintroductionofthesmallpremiumPETwatersthecategorystartedtoexplode"saysMr.Bellas."ThebottledwaterindustrybeforePETonthelistofallbeveragecategorieswasnumberseven.WiththeadventofPETwaterjumpedtothenumbertwospotbehindcarbonatedsoftdrinks." Bybrandingandmarketingwaterbottledwaterhasbeentransformedfromsomethingthatmanyofustookforgrantedintoaproductthatnowmakesbillionsforglobalmultinationalcompanies. 43
有5个进程PaPbPcPd和Pe它们依次进入就绪队列它们的优先级和需要的处理机时间如表2-14所示表2-14进程—处理机—优先级表进程处理机时间优先级Pa103Pb11Pc23Pd14Pe52忽略进程调度等所花费的时间请回答下列问题1分别写出采用先来先服务和非抢占式的优先数优先数大优先级低调度算法选中进程执行的次序2分别计算出上述两种算法使各进程在就绪队列中的等待时间及两种算法下的平均等待时间3某单处理机系统中采用多道程序设计现有10个进程存在则处于运行阻塞和就绪状态的进程数量最小和最大值分别可能是多少
Researchersinvestigatingbrainsizeandmentalabilitysaytheirworkoffersevidencethateducationprotectsthemindfromthebrain’sphysicaldeterioration. 46Itisknownthatthebrainshrinksasthebodyagesbuttheeffectsonmentalabilityaredifferentfrompersontoperson.Interestinglyinastudyofelderlymenandwomenthosewhohadmoreeducationactuallyhadmorebrainshrinkage. "Thatmayseemlikebadnews"saidstudyauthorDr.EdwardCoffeyaprofessorofpsychiatryandofneurologyatHenryFordHealthSysteminDetroit.47Howeverheexplainedthefindingsuggeststhateducationallowspeopletowithstandmorebraintissuelossbeforetheirmentalfunctioningbeginstobreakdown. ThestudypublishedintheJulyissueofNeurologyisthefirsttoprovidebiologicalevidencetosupportaconceptcalledthe"reserve"hypothesisaccordingtotheresearchers.Inrecentyearsinvestigatorshavedevelopedtheideathatpeoplewhoaremoreeducatedhavegreatercognitivereservestodrawuponasthebrainages;inessencetheyhavemorebraintissuetospare. 48Examiningbrainscansof320healthymenandwomenaged66to90researchersfoundthatforeachyearofeducationthesubjectshadtherewasgreatershrinkageoftheouterlayerofthebrainknownasthecortex.Yetontestsofcognitionandmemoryallparticipantsscoredintherangeindicatingnormal. "Everyonehassomedegreeofbrainshrinkage."Coffeysaid."Peopleloseonaverage2.5percentperdecadestartinginadulthood." Thereishowevera"remarkablerange"ofshrinkageamongpeoplewhoshownosignsofmentaldeclineCoffeynoted.Overallhealthhesaidaccountsforsomedifferencesinbrainsize.Alcoholordruguseaswellasmedicalconditionssuchasdiabetesandhighbloodpressurecontributetobraintissuelossthroughoutadulthood. IntheabsenceofsuchmedicalconditionsCoffeysaideducationlevelhelpsexplaintherangeofbrainshrinkageexhibitedamongthementally-fitelderly.Themore-educatedcanwithstandgreaterloss. 49Coffeyandcolleaguesgaugedshrinkageofthecortexbymeasuringthecerebrospinalfluid脑脊液surroundingthebrain.Thegreatertheamountoffluidthegreaterthecortical脑皮层的shrinkage. Controllingforthehealthfactorsthatcontributetobraininjurytheresearchersfoundthateducationwasrelatedtotheseverityofbrainshrinkage.Foreachyearofeducationfromfirstgradeonsubjectshadanaverageof1.77milliliters11morecerebrospinalfluidaroundthebrain.Justhoweducationmightaffectbraincellsisunknown.50Intheirreporttheresearchersspeculatedthatinpeoplewithmoreeducationcertainbrainstructuresdeeperthanthecortexmaystayintacttocompensateforcorticalshrinkage. 49Coffeyandcolleaguesgaugedshrinkageofthecortexbymeasuringthecerebrospinalfluid脑脊液surroundingthebrain.Thegreatertheamountoffluidthegreaterthecortical脑皮层的shrinkage.
ThemostthoroughlystudiedintellectualsinthehistoryoftheNewWorldaretheministersandpoliticalleadersofseventeenth-centuryNewEngland.AccordingtothestandardhistoryofAmericanphilosophynowhereelseincolonialAmericawas“somuchimportanceattachedtointellectualpursuits.”AccordingtomanybooksandarticlesNewEngland’sleadersestablishedthebasicthemesandpreoccupationsofanunfoldingdominantPuritantraditioninAmericanintellectuallife. TotakethisapproachtotheNewEnglandersnormallymeanstostartwiththePuritans’theologicalinnovationsandtheirdistinctiveideasaboutthechurch—importantsubjectsthatwemaynotneglect.ButinkeepingwithourexaminationofsouthernintellectuallifewemayconsidertheoriginalPuritansascarriersofEuropeancultureadjustingtoNewWorldcircumstances.TheNewEnglandcolonieswerethescenesofimportantepisodesinthepursuitofwidelyunderstoodidealsofcivilityandvirtuosity. TheearlysettlersofMassachusettsBayincludedmenofimpressiveeducationandinfluenceinEngland.BesidestheninetyorsolearnedministerswhocametoMassachusettschurchesinthedecadeafter1629therewerepoliticalleaderslikeJohnWinthropaneducatedgentlemanlawyerandofficialoftheCrownbeforehejourneyedtoBoston.ThesemenwroteandpublishedextensivelyreachingbothNewWorldandOldWorldaudiencesandgivingNewEnglandanatmosphereofintellectualearnestness. WeshouldnotforgethoweverthatmostNewEnglanderswerelesswelleducated.Whilefewcraftsmenorfarmersletalonedependentsandservantsleftliterarycompositionstobeanalyzeditisobviousthattheirviewswerelessfullyintellectualized.Theirthinkingoftenhadatraditionalsuperstitiousquality.AtailornamedJohnDanewhoemigratedinthelate1630sleftanaccountofhisreasonsforleavingEnglandthatisfilledwithsigns.Sexualconfusioneconomicfrustrationsandreligioushope—allcametogetherinadecisivemomentwhenheopenedtheBibletoldbasfatherthatthefirstlinehesawwouldsettlehisfateandreadthemagicalwords:"ComeoutfromamongthemtouchnouncleanthingandIwillbeyourGodandyoushallbemypeople."OnewonderswhatDanethoughtofthecarefulsermonsexplainingtheBiblethatheheardinPuritanchurches. MeanwhilemanysettlershadslighterreligiouscommitmentsthanDane’sasoneclergymanlearnedinconfrontingfolkalongthecoastwhomockedthattheyhadnotcometotheNewWorldfurreligion."Ourmainendwastocatchfish. ThestoryofJohnDaneshowsthatlesswell-educatedNewEnglanderswereoften
假设一个计算机系统具有如下性能特征处理一次中断平均耗用1毫秒一次进程调度平均需要2毫秒将CPU分配给选中的进程又需要平均1毫秒再假设其定时器芯片每秒产生100次中断请回答1操作系统将百分之几的CPU时间用于时钟中断处理2如果操作系统采用轮转法调度10个时钟中断为1个时间片那么操作系统将百分之几的CPU时间用于进程调度包括调度分配CPU和引起调度的时钟中断处理时间
[A]Convenientpackaging [B]Healthandwellness [C]Skepticalcustomers [D]Enormousmarkets [E]Soaringsales [F]Trendydrink Inthelast40yearsthebottledwaterindustryhasgonefromabusinessprospectthatfewtookseriouslytoaglobalindustryworthbillionsofpounds.Thecommodityitselfremainssimple.Thewaywethinkaboutithaschangedfundamentally.Waterisnaturalpureandsourcedatminimalcost.Itsrealvalueliesinitsmarketingandbranding."Ithinkbottledwateristhemostrevealingsubstanceforshowingushowtheglobalcapitalistmarketworkstoday"saysRichardWilkprofessorofanthropologyatIndianaUniversity."Inasensewe’rebuyingchoicewe’rebuyingfreedom.That’stheonlythingthatcanexplainwhyyouwouldpaymoneyforabottleofsomethingthatyoucanotherwisegetforfree." 41.______ Throughaconfectionofadvertisingandmarketingbottledwaterhasbecomeoneofthebiggestsuccessstoriesinthemodernfoodandbeverageindustry."Thedemandforbottlewaterhasgrownexponentiallyinthelastfewdecades"saysDr.PeterGleickauthorofBottledandSold."It’sdoubledit’sdoubledagainandit’sdoubledagain.Andthebottlewatercompaniesseeenormousmarketsnotjustintherichcountriesbutalsointhepoorercountries." Noactualvariety Somepeoplethinkthatbottledwateristhehighpointofglobalcapitalismparticularlythepeopleinthebottledwaterbusiness."Ithinkbottledwateractuallyrepresentsakindofcaricatureoftheglobaleconomy.Itprovidespeopleinthedevelopedworldwith20or30varietiesofsomethingforwhichthereisnoactualvariety"saysCharlesFishmanauthorofTheBigThirst. 42.______. Atthebeginningtherereallywasnovarietyandthebottledwaterphenomenonbeganwithonebrand.Perrier佩绿雅矿泉水品牌wasatriumphofadvertisingcreatingabrandthatwastodefineageneration.AttheheartofthecampaigntomakethebrandpopularwasRichardWheatleyoftheLeoBurnettadvertisingagencybetween1979and1994."Perrierpopularisedbottledwater"hesays."Itmadeitacceptablemorethanacceptableitmadeit...desirable."Butitwasnotaninstantsuccess.WhenPerrierUKwaslookingtoincreaseitssalesintheearly1970’sitfacedaskepticalpublic.Manyquestionedwhyanyonewouldbuywaterwhenyoucouldgetitfreefromthetap. 43.______. FacedwithobstaclesPerrierturnedtoadvertisingwithacampaignthatwastochangeourconsumerlandscapeforever.Thecampaignwasamarketingcoupandsaleswentthroughtherooffrom12millionbottlesin1980to152millionbytheendofthedecade.Perrierwasnolongerjustabottleofwater.Themarketingandadvertisingteamshadestablishedacrucialemotionallinkbetweentheproductandtheconsumers."Perrierbecameabadge"saysMichaelBellaschairmanoftheBeverageMarketingCorporation."WhenyouheldaPerrierbottleupitsaidsomethingaboutyourselfitsaidyouweresophisticatedyouunderstoodwhatwashappeningintheworld.Itwasaperfectbeveragefortheyoungandcomingbusinessexecutivesthetrend-setters." 44.______. Inanageofinstantgratificationstillwaterinportablebottlesprovidedwhatpeopleneededexactlywhentheyneededit."Peopleingeneralaremoreandmoretimepressed"saysMr.Fishman."Wedon’tcookourownmealsanymoreweeatpreparedfoodsofallkinds.Andthere’snothingmoreappealingthanabottleofcoldwateratamomentwhenyou’rereallythirsty.ButIthinkbottledwaterisoneofthoseproductsthatonmanyoccasionswhenpeoplebuyitwhatthey’rebuyingisn’tthewatersomuchasthebottle.Thatisthepackageandtheconvenienceatthatmoment." 45.______. WhenpeopleboughtthisconveniencewhattheywerereallybuyingwasPolyethyleneTerephthalateorPETthesinglemostimportantinnovationintheindustry’shistory.StrongshatterproofandahighlyvaluedformofpolyesterPETisaby-productoftheoilindustry.Itisnowutilisedinthepackagingofeverythingfrompharmaceuticalsandsoaptoreadymeals.InyearstocometheenvironmentalimpactofPETwouldhaunttheindustryandraisequestionsaboutitsverysurvivalbutinthe1990sthiswasarevolution.AccordingtoMr.Bellasitwasbehindthesubsequentincrediblegrowthoftheindustry."StartingwiththeintroductionofthesmallpremiumPETwatersthecategorystartedtoexplode"saysMr.Bellas."ThebottledwaterindustrybeforePETonthelistofallbeveragecategorieswasnumberseven.WiththeadventofPETwaterjumpedtothenumbertwospotbehindcarbonatedsoftdrinks." Bybrandingandmarketingwaterbottledwaterhasbeentransformedfromsomethingthatmanyofustookforgrantedintoaproductthatnowmakesbillionsforglobalmultinationalcompanies. 41
Gallowayamostlymiddle-classcommunitynorthwestofAtlanticCityispartofawaveofdistrictsacrossthenationtryingtoremakehomeworkamidconcernsthathigh-stakestestingandcompetitionforcollegehavefueledanightlygrindthatisstressingoutchildrenanddeprivingthemofplayandrestyetdoinglittletoraiseachievementparticularlyinelementarygrades. Sucheffortshavedrawncriticismfromsometeachersandsomeparentswhocounterthatstudentsmuststudymorenotlessiftheyaretosucceed.Evensotheanti-homeworkmovementhasbeenreignitedinrecentmonthsbythedocumentaryRacetoNowhereaboutburned-outstudentscaughtinapressure-cookereducationalsystem."Thereissimplynoproofthatmosthomeworkasweknowitimprovesschoolperformance"saidVickiAbelesthefilmmakerandamotherofthreefromCalifornia."Andbyexpectingkidstoworka’secondshift’inwhatshouldbetheirdowntimethepresenceofschoolworkathomeisnegativelyaffectingthehealthofouryoungpeopleandthequalityoffamilytime." SoteachersatMangoElementarySchoolinFontanaCalif.arereplacinghomeworkwith"goalwork"thatisspecifictoindividualstudent’sneedsandthatcanbecompletedinclassorathomeathisorherownpace.TheBrooklynSchoolofInquiryagiftedandtalentedprogramhasmadehomeworkoptional."Ithinkpeopleconfusehomeworkwithrigor"saidDonnaTaylortheBrooklynSchool’sprincipalwhoviewshomeworkforchildrenunder11asprimarilybenefitingparentsbyhelpingthemfeelconnectedtotheclassroom. Researchhaslongsuggestedthathomeworkinsmalldosescanreinforcebasicskillsandhelpyoungchildrendevelopstudyhabitsbutthattherearediminishingreturns.Stilleffortstorollbackhomeworkhavebeenopposedbythosewhocounterthatthereisnotenoughtimeintheschooldaytocoverrequiredtopicsandthathomeworkreinforcesclassroomlearning.InCoronadoCalif.theschoolboardrejectedaproposalbythesuperintendenttoeliminatehomeworkonweekendsandholidaysaftersomeparentssaidthatwaswhentheyhadtimetohelptheirchildrenandothersworrieditwouldresultinmorehomeworkonweeknights. Homeworkwarshavedividedcommunitiesforoveracentury.Inthe1950stheSputniklaunchingusheredinheavierworkloadsforAmericanstudentsintheracetokeepupwiththeSovietUnion.The1983report"ANationatRisk"andmorerecentlythetestingpressuresoftheNoChildLeftBehindlawalsoresultedinmorehomeworkforchildrenatyoungerages.Afewpublicandprivateschoolshaverenouncedhomeworkinrecentyearsbutmosthavesoughtamiddleground.InGallowaythepolicywouldstipulatethathomeworkcoveronlytopicsalreadyaddressedinclass.Dr.GiaquintoGalloway’ssuperintendentsaidthegoaloftheproposedpolicywastomakehomework"meaningfulandmanageable"notingthatteacherswouldhavetocoordinateassignmentssothatastudent’stotalhomeworkwouldnotexceedthetimelimit. Increasedhomeworkhadresultedfrom
某系统中进程有如图2-16所示的状态变化 请回答下列问题 把图中发生①～④的状态变化原因填入表2-12中
设系统中有下述解决死锁的办法1银行家算法2检测死锁终止处于死锁状态的进程释放该进程所占有的资源3资源预分配请问哪种办法允许最大的并发性即哪种办法允许更多的进程无等待地向前推进请按并发性从大到小对上述三种办法进行排序
ThemostthoroughlystudiedintellectualsinthehistoryoftheNewWorldaretheministersandpoliticalleadersofseventeenth-centuryNewEngland.AccordingtothestandardhistoryofAmericanphilosophynowhereelseincolonialAmericawas“somuchimportanceattachedtointellectualpursuits.”AccordingtomanybooksandarticlesNewEngland’sleadersestablishedthebasicthemesandpreoccupationsofanunfoldingdominantPuritantraditioninAmericanintellectuallife. TotakethisapproachtotheNewEnglandersnormallymeanstostartwiththePuritans’theologicalinnovationsandtheirdistinctiveideasaboutthechurch—importantsubjectsthatwemaynotneglect.ButinkeepingwithourexaminationofsouthernintellectuallifewemayconsidertheoriginalPuritansascarriersofEuropeancultureadjustingtoNewWorldcircumstances.TheNewEnglandcolonieswerethescenesofimportantepisodesinthepursuitofwidelyunderstoodidealsofcivilityandvirtuosity. TheearlysettlersofMassachusettsBayincludedmenofimpressiveeducationandinfluenceinEngland.BesidestheninetyorsolearnedministerswhocametoMassachusettschurchesinthedecadeafter1629therewerepoliticalleaderslikeJohnWinthropaneducatedgentlemanlawyerandofficialoftheCrownbeforehejourneyedtoBoston.ThesemenwroteandpublishedextensivelyreachingbothNewWorldandOldWorldaudiencesandgivingNewEnglandanatmosphereofintellectualearnestness. WeshouldnotforgethoweverthatmostNewEnglanderswerelesswelleducated.Whilefewcraftsmenorfarmersletalonedependentsandservantsleftliterarycompositionstobeanalyzeditisobviousthattheirviewswerelessfullyintellectualized.Theirthinkingoftenhadatraditionalsuperstitiousquality.AtailornamedJohnDanewhoemigratedinthelate1630sleftanaccountofhisreasonsforleavingEnglandthatisfilledwithsigns.Sexualconfusioneconomicfrustrationsandreligioushope—allcametogetherinadecisivemomentwhenheopenedtheBibletoldbasfatherthatthefirstlinehesawwouldsettlehisfateandreadthemagicalwords:"ComeoutfromamongthemtouchnouncleanthingandIwillbeyourGodandyoushallbemypeople."OnewonderswhatDanethoughtofthecarefulsermonsexplainingtheBiblethatheheardinPuritanchurches. MeanwhilemanysettlershadslighterreligiouscommitmentsthanDane’sasoneclergymanlearnedinconfrontingfolkalongthecoastwhomockedthattheyhadnotcometotheNewWorldfurreligion."Ourmainendwastocatchfish. Itissuggestedinparagraph2thatNewEnglanders
Researchersinvestigatingbrainsizeandmentalabilitysaytheirworkoffersevidencethateducationprotectsthemindfromthebrain’sphysicaldeterioration. 46Itisknownthatthebrainshrinksasthebodyagesbuttheeffectsonmentalabilityaredifferentfrompersontoperson.Interestinglyinastudyofelderlymenandwomenthosewhohadmoreeducationactuallyhadmorebrainshrinkage. "Thatmayseemlikebadnews"saidstudyauthorDr.EdwardCoffeyaprofessorofpsychiatryandofneurologyatHenryFordHealthSysteminDetroit.47Howeverheexplainedthefindingsuggeststhateducationallowspeopletowithstandmorebraintissuelossbeforetheirmentalfunctioningbeginstobreakdown. ThestudypublishedintheJulyissueofNeurologyisthefirsttoprovidebiologicalevidencetosupportaconceptcalledthe"reserve"hypothesisaccordingtotheresearchers.Inrecentyearsinvestigatorshavedevelopedtheideathatpeoplewhoaremoreeducatedhavegreatercognitivereservestodrawuponasthebrainages;inessencetheyhavemorebraintissuetospare. 48Examiningbrainscansof320healthymenandwomenaged66to90researchersfoundthatforeachyearofeducationthesubjectshadtherewasgreatershrinkageoftheouterlayerofthebrainknownasthecortex.Yetontestsofcognitionandmemoryallparticipantsscoredintherangeindicatingnormal. "Everyonehassomedegreeofbrainshrinkage."Coffeysaid."Peopleloseonaverage2.5percentperdecadestartinginadulthood." Thereishowevera"remarkablerange"ofshrinkageamongpeoplewhoshownosignsofmentaldeclineCoffeynoted.Overallhealthhesaidaccountsforsomedifferencesinbrainsize.Alcoholordruguseaswellasmedicalconditionssuchasdiabetesandhighbloodpressurecontributetobraintissuelossthroughoutadulthood. IntheabsenceofsuchmedicalconditionsCoffeysaideducationlevelhelpsexplaintherangeofbrainshrinkageexhibitedamongthementally-fitelderly.Themore-educatedcanwithstandgreaterloss. 49Coffeyandcolleaguesgaugedshrinkageofthecortexbymeasuringthecerebrospinalfluid脑脊液surroundingthebrain.Thegreatertheamountoffluidthegreaterthecortical脑皮层的shrinkage. Controllingforthehealthfactorsthatcontributetobraininjurytheresearchersfoundthateducationwasrelatedtotheseverityofbrainshrinkage.Foreachyearofeducationfromfirstgradeonsubjectshadanaverageof1.77milliliters11morecerebrospinalfluidaroundthebrain.Justhoweducationmightaffectbraincellsisunknown.50Intheirreporttheresearchersspeculatedthatinpeoplewithmoreeducationcertainbrainstructuresdeeperthanthecortexmaystayintacttocompensateforcorticalshrinkage. 47Howeverheexplainedthefindingsuggeststhateducationallowspeopletowithstandmorebraintissuelossbeforetheirmentalfunctioningbeginstobreakdown.
设某计算机系统有一块CPU一台输入设备一台打印机现有两个进程同时进入就绪状态且进程A先得到CPU运行进程B后运行进程A的运行轨迹为计算50毫秒打印信息100毫秒再计算50毫秒打印信息100毫秒结束进程B的运行轨迹为计算50毫秒输入数据80毫秒再计算100毫秒结束试说明进程A运行时有无等待现象若有在什么时候发生等待现象
某一个操作系统具有分时兼批处理的功能设计一个合理的队列调度策略使得分时作业响应快批作业也能及时得到处理
系统有同类资源10个进程P1P2和P3需要该类资源的最大数量分别为867它们使用资源的次序和数量如表2-11所示试给出采用银行家算法分配资源时进行第5次分配后各进程的状态及各进程占用资源的情况
设有一个公有信箱和若干个私有信箱公有信箱可由所有人在其中存/取信件而私有信箱只能由特定拥有者使用在其中存/取信件显然信箱是有容量限制的选定一种信号量机制设计出相应的同步机制管理程序
某系统有R1R2和R3共3种资源在T0时刻P1P2P3和P4这4个进程对资源的占有和需求情况如表2-10所示此刻系统可用资源向量为212问题如果此时P1和P2均发出资源请求向量Request101为了保持系统安全性应该如何分配资源给这两个进程说明所采用的原因
进程和线程的主要区别是什么
Gallowayamostlymiddle-classcommunitynorthwestofAtlanticCityispartofawaveofdistrictsacrossthenationtryingtoremakehomeworkamidconcernsthathigh-stakestestingandcompetitionforcollegehavefueledanightlygrindthatisstressingoutchildrenanddeprivingthemofplayandrestyetdoinglittletoraiseachievementparticularlyinelementarygrades. Sucheffortshavedrawncriticismfromsometeachersandsomeparentswhocounterthatstudentsmuststudymorenotlessiftheyaretosucceed.Evensotheanti-homeworkmovementhasbeenreignitedinrecentmonthsbythedocumentaryRacetoNowhereaboutburned-outstudentscaughtinapressure-cookereducationalsystem."Thereissimplynoproofthatmosthomeworkasweknowitimprovesschoolperformance"saidVickiAbelesthefilmmakerandamotherofthreefromCalifornia."Andbyexpectingkidstoworka’secondshift’inwhatshouldbetheirdowntimethepresenceofschoolworkathomeisnegativelyaffectingthehealthofouryoungpeopleandthequalityoffamilytime." SoteachersatMangoElementarySchoolinFontanaCalif.arereplacinghomeworkwith"goalwork"thatisspecifictoindividualstudent’sneedsandthatcanbecompletedinclassorathomeathisorherownpace.TheBrooklynSchoolofInquiryagiftedandtalentedprogramhasmadehomeworkoptional."Ithinkpeopleconfusehomeworkwithrigor"saidDonnaTaylortheBrooklynSchool’sprincipalwhoviewshomeworkforchildrenunder11asprimarilybenefitingparentsbyhelpingthemfeelconnectedtotheclassroom. Researchhaslongsuggestedthathomeworkinsmalldosescanreinforcebasicskillsandhelpyoungchildrendevelopstudyhabitsbutthattherearediminishingreturns.Stilleffortstorollbackhomeworkhavebeenopposedbythosewhocounterthatthereisnotenoughtimeintheschooldaytocoverrequiredtopicsandthathomeworkreinforcesclassroomlearning.InCoronadoCalif.theschoolboardrejectedaproposalbythesuperintendenttoeliminatehomeworkonweekendsandholidaysaftersomeparentssaidthatwaswhentheyhadtimetohelptheirchildrenandothersworrieditwouldresultinmorehomeworkonweeknights. Homeworkwarshavedividedcommunitiesforoveracentury.Inthe1950stheSputniklaunchingusheredinheavierworkloadsforAmericanstudentsintheracetokeepupwiththeSovietUnion.The1983report"ANationatRisk"andmorerecentlythetestingpressuresoftheNoChildLeftBehindlawalsoresultedinmorehomeworkforchildrenatyoungerages.Afewpublicandprivateschoolshaverenouncedhomeworkinrecentyearsbutmosthavesoughtamiddleground.InGallowaythepolicywouldstipulatethathomeworkcoveronlytopicsalreadyaddressedinclass.Dr.GiaquintoGalloway’ssuperintendentsaidthegoaloftheproposedpolicywastomakehomework"meaningfulandmanageable"notingthatteacherswouldhavetocoordinateassignmentssothatastudent’stotalhomeworkwouldnotexceedthetimelimit. Criticismsofhomeworkaremainlybasedonthepremisethat
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