Operating SystemsIntroductionAbout this course…Expect (Some) PainWhat Works & Doesn’tWhy So Many Grades?Some ReliefThere Is No MagicMechanics – InfoMechanics – GradingMechanics - PeopleMechanics – ReadingsMechanics - ProjectsSend Me Your DetailsWhat Is an OS?Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Mechanism & PolicyIs There a Perfect OS?Is Any OS Complete?History LessonsHistorical ComparisonConstant Employment?May You Live in Interesting Times…Send To vivek@cs…And Now For Something Completely Different…Operating SystemsVivek PaiLecture 1Sep 12, 2002Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 2IntroductionWho I amVivek PaiPhD 99/00, RiceResearch: OS, networking, high-performance appsWhy I do thisFunInterestingDesign opportunities“Profitable”Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 3About this course…PrinciplesOS designSome theoryRationalePracticeNot trade schoolGoalsUnderstand OS decisionsBasis for future learningGet hands dirtyNot “elite hacker”Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 4Expect (Some) PainFast paceLots of projects (programming)Hard materialCourse changing based on feedbackNot the end of the world – course favorably received last year, under much more trying circumstancesSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 5What Works & Doesn’tWorksSolid C backgroundFlexible approachGrasping PrereqsOpen mindEinsteinFeedback sheetsDoesn’tSchedule overloadMissing backgroundMathematical precisionSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 6Why So Many Grades?Programming projectsMidterm & final examsQuizzes (see me about health/school absences)Intended to reduce pressure/anxietyMore data points = less noiseSomewhat generous extra creditSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 7Some ReliefGrades based on mean/deviationPeople have done generally well in the past25 / 38 As17 / 11 Bs4 / 7 CsHonor SystemUse common senseAsk for clarificationCooperation OKWork is your own(pairs for labs)Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 8There Is No MagicThis Is EngineeringTradeoffsConstraintsOptimizationsImperfectionNothing’s PermanentHigh rate of changeLots of inertiaCost/benefit analysesHuman errorSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 9Mechanics – InfoMy home pageCourse home pageNewsgroupPreceptsDesign reviewsSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 10Mechanics – GradingAssigned readings20% quizzes20% midterm20% final40% projects – some extra creditLate policy: 6 hours: 91%12 hours: 84%24 hours: 71%48 hours: 50%Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 11Mechanics - PeopleSee web site – it’s up to date!Basically–Me – quizzes, exams–TAs – precepts, labs–Office hours – T, W, Th or by ApptSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 12Mechanics – ReadingsModern Operating SystemsTannenbaumDifferent from last timeAvailable at UstoreVarious readings – will be available from my home page (course web site)Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 13Mechanics - Projects6 projects, 2 themes–Build parts of a mini-OS–Write applications that interact with OS2 weeks eachUses Linux, sort ofPartners – be decent to each otherOption – one big project – only for the braveSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 14Send Me Your DetailsNameYearMajorE-mail addressPhone #Picture via URLWhy you’re taking the classWhat you’d like/hope to learnSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 15What Is an OS?Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 16What Is an OS?“Code” that:Sits between programs & hardwareSits between different programsSits betweens different usersBut what does it do?Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 17What Is an OS?ResourcesAllocationProtectionReclamationVirtualizationServicesAbstractionSimplificationConvenienceStandardizationMakes computers simplerSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 18What Is an OS?ResourcesAllocationProtectionReclamationVirtualizationFinite resourcesCompeting demandsExamples:CPUMemoryDiskNetworkSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 19What Is an OS?ResourcesAllocationProtectionReclamationVirtualizationYou can’t hurt meI can’t hurt youImplies some degree of safety & securitySep 12, 2002 COS 318 - Operating Systems, Vivek Pai 20What Is an OS?ResourcesAllocationProtectionReclamationVirtualizationThe OS givethThe OS taketh awayVoluntary at run timeImplied at terminationInvoluntaryCooperativeSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 21What Is an OS?ResourcesAllocationProtectionReclamationVirtualizationIllusion of infinite, private resourcesMemory versus diskTimeshared CPUMore extreme cases possible (& exist)Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 22Mechanism & PolicyMechanism – tool to achieve some effectPolicy – decisions on how to use toolExamples:All users treated equallyAll program instances treated equallyPreferred users treated betterNo deterministic behavior at allSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 23Is There a Perfect OS?Sep 12, 2002 COS 318 - Operating Systems, Vivek Pai 24Is Any OS Complete?PortabilitySecurityFairnessRobustnessEfficiencyInterfacesSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 25History Lessons60’s-70’s - MainframesRise of IBM70’s - 80’s – MinicomputersRise of Digital Equipment80’s - 90’s – PCsRise of Intel, MicrosoftNow – Post-PCDistributed applicationsSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 26Historical ComparisonMainframe Mini MicroSystem $/worker10:1 – 100:110:1 – 1:11:10-1:100Goal System utilizationOverall costProductivityTarget Capacity Features Ease of UseSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 27Constant Employment?New hardwareNew featuresNew approachesExamples: Palm, Java, WWWSep 12, 2002 COS 318 - Operating Systems, Vivek Pai 28May You Live in Interesting Times…Processors double in 18 monthsDisk doubling every 12 monthsGlobal bandwidth every 6 months“Sweet spot” constantly decayingDo people ever double?Sep 12, 2002 COS 318 - Operating Systems,