mputerarchitecture HE memory Ilo system Operating controls andcoordinateshardwareamongvariousapplicationsanduses IE c fooplemachines computersnetworks is responsibletomakeusingthecomputer a good experience andhave it takescare of all resource utilization itself viiiit if of programs controlsexecution iii iii iii Iiii perform well me www ve.in userexpectation handleserrorsinterrupts manages I10andinterprets basedonwhatit's Thefunctionality oftheaswillbeextremelydifferent supposed to do 45pp.ttnuitipleusers at thesametime I part oneuserat atime Questions servers sharingconnecttoexternalresourcessuch as printersweb Is secondarystorage I10 whatisthestoragehierarchyfor ifage Doesn'tswitchingbetween processes ofoverhead causelots having to recache allthedatarequired forthe process I p Lthe mainpart ofthe0s iii If ii stain Does a zombiewhobecomesan orphangetreaped Tufty bythesystemforits use created Applicationprogram processes createdfor usebyuserapplications Bootstrapprogram firstthingthat's loadedwhenthecomputeristurned in Loaded fromthe RomEPROM typically istheonlythingonthese known as firmware Initializesthesystem startsthekernel 10 structure I A ruptstheos whentheyneedattention multiplecanhappen at thesametime sotheyare assigned differentlevels I device inmemory aching mm i theneededdateis there unity if no it iscopied to conethenused cachesarefrequentlyverysmall insize rectMemoryAccess Largeamountsof data istransferedin blocks to avoid lotsofoverheadandinterrupts mputerSystem Architecture sxm.me Ii in common msanaesametasks desktopsandlaptops Asymmetricmulti processing eachprocessoris assigned a specifictask is commononphones ultiprocessor vsMulticore Iii If iit.is surereau.tsnem inactivethingsat e a sum tie 05 structure in items organizessons sotheCru isneveridle rapidlyswitchesbetweenjobswhencaused towaitandschedule Timesharingmultitasking conswitchesbetweenjobsextremelyquicklycreatingthe illusion of t.itIf ihIEdosiceuwhile processes of multiplethingsbeingexecuted at once are beingexecuted usescanscheduling to efficientlymanage processexecution if processesdonot fit inmemory swappingthemmovesthem inandoutsotheycanrun L.cn fihtewseefitastise'smemorytoallowexecutionofprocesses in runningprocesses secondary storage is oftenslowerthanmainmemory ILefttopreventprocesses runninginfinitely isdecrementedby a physicalclock watchdog timefrom2030 counter Lecture 2 05 Responsibilities process Management Arunningprogram is a process programis passive process isactive processes need resources Ceuspace I 0 files terminatingprocesses reclaims thereusable resources single threadedprocesseshave one4C processes executetheircodesequentially onePCperthread multithreadedhave Typicallysystemhasmany processessameuser same as theCPUs running concurrentlyon TheOs is responsibleforthese in relation toprocesses creatingdeletingprocesses suspending resumingprocesses supporting synchronization communication.gg fifefE an another n Memory Management Toexecute a program at leastsomeofthe instructions mostofthetimeall samewiththedataneeded bytheprogram memorymanagement handles oftheinstructionsmustbein memory thehousekeeping ofdeterminingwhatwhereandwhenthings are inmemory memory management activities ofhowmemory isbeingusedandbywhom managinghowprocesses we moved inandout ofmemory keepingtrack Allocating deallocatingmemoryspaceasneeded Storage Management Osisdesignedto provide a logical viewof information storage unit file by a device diskdrivesolidstatedrive thingssuchas speedcapacitytransfer rateshould all beconsideredwhenpicking Abstractsphysical propertiesto logicalstorage eachmediumiscontrolled I fi EEi ieamn n.cnnaasa managementof files directories Primitivesto manipulate filesanddirectories Mappingfilesto secondary storage Backupfilesontostable nonvolatile storage Free Space management storageallocation Disk scheduling Entirespeedofcomputerhinges on thesubsystems of secondary storage an opticaldisksmagnetictapes readwrite variesbetween WORM writeoncereadmany and RWC I 0 Subsystem us manages ffers 3 spooling theoverlappingofoutputofonejobwithoutputof mother generaldevice driverinterface Drivers for specifichardwaredevices computing Environments standalonegeneralpurposemachines ftpuidewebaccesstointernalsystems Networkcomputersakathinclients networks Mobilecomputersinterconnectviawireless Di P Iratesystemsreturned network is a it together communication pathwhere ICP IQ arethemostcommon iii Else tiggams ins returns ClientserverComputing iii iiii.iiiii.itiian.sa Fileserversystemprovidesinterface forclientstostoreandretrievefiles n.n and its algorithms to peer notdistinguishbetweenclientsandservers Does insteadallnodesareconsideredpeers eachactasclientseverorboth many E.EE II I am applications withotheroses usedwhensourceCputypedifferentfromtarget E.mywtim I in.nu Tfeffingfor multiplesystems Is Ftingstorageand networks appsasservices across toanyonewilling t.tt internet Impany forcompany'suse fifesshhpublicandprivatecloudcomponents Softuneas a service softwareyoucanrent platform as a service forapplicationovertheinternet softwarestack ready Infrastructureas a service torent servesstorageavailable The process concept Anoperating system executes a varietyofprograms Bitp systems Timeshared systems userprograms tasks Forthiscoursejob process process executionmustprogress insequentialfashion u u of Components a process APC progressregisters Includes astackhempData and text tinitialized globalstaticvariables initialized is nonzerononNULL uninitializedglobalstaticvariables zeroor uninitializedvariables Heifynamic memoryallocation trickyifmanagedby os because programmightneed a biggertempthan whatwasassigned IEE eamaerarmautomatic t.EE is it t.EE thefunctionshouldreturnto Keepsthepointwhere mean New brandnew processbeingcreated Running beingexecuted waitingwaitingforanevent re P beassignedto a processor Terminated finished stopped itsexecution Linux byanexternalprocess suspended doesnotnecessarilymean zombie Linux it wasterminated finished executing butisstillreferenced bythesystem Process Control Black Infoassociatedwitheach PCB is called a taskcontrolblack This isjustinfoabout theprocess i e info scheduling es It ca beenactive cenused takenup I 0Info mtextswitch Is info bythe PCB represented Timeit takes toswitchprocesses is overhead more complex CBs tepsto switch process savethestate of 91 process 1 Orocess scheduling forquickswitchingbetweenprocesses ontotheCPUfortimesharing Allows Keepsa scheduleoftheprocesses needingservice selectsfrom itsqueueforthenextprocesstobe serviced Jobqueue Allprocesses Ready queue Allprocessesinmemory needingservice Device queue processeswaitingfor I odevices Schedulers Shortterm scheduler akaCpuscheduler selects whichprocesstobeexecutednext shorttermschedule is invokedasoftenasmillisecondsspeediskey Longtermscheduler areajobschedule t.it EI t.ae of presses mediumscheduler optimal used ifthedegreeof multiple programmingneedsto bereduced movesprocessesfrommemory e todisktostoreandbacktoexecute ii in I finaltime on In conbound usescan frequently forshortperiodsoftime doescomputations over I 0 smallnumberof longCeuusages operations on Processes Resource sharingoptions IL ftp.rent'sresources Parentandchildrenshareno resources Executionoptions Iiato Background suspended I terminatebeforecontinuing processes willnotrespondtokeyboardcommands assumethisalso meanstheywon'trespond to otherinput hekillcommand is notignorablebyprocesses Important Libraries If see frapper In factions Systypes.in syswait.in EE.im tin Y m.it d n iiiiiii'iii returned t.ae and Bothprocessescontinuerightafterforkwascalled Thechildcanalsohaveanotherprogram landedinto it viii iii iii iii iii Returnvalues t.int ItYofchild current process isparent weclone Inexist ofeachother sometimesparentshaveto write forsome allchildren toterminate beforetheycancontinue independently childrenwhoseparentsterminate beforethembecome orphans mayterminatetheirchildrenwithabort parents fifth h t.fi aaan www.n whenmenterminate a familytreeofprocesses sotheoriginaleventon terminate W.ITdstheexecution of thecurrent process untilare of itschildren terminates iiiuiiistei.imea Ii level differentbitshavedifferent III EffyThe for an exitscaries meaning numbers Zombies Orphans zombiesare processeswhichterminated automatically staysthiswayuntilreapedwith a write call bytheparent orphansare reapedautomatically
