Computer Organization and Architecture - Chapter 1: Introduction

Architecture is those attributes visible to theprogrammer:Instruction set, number of bits used for datarepresentation, I/O mechanisms, addressingtechniques.e.g. Is there a multiply instruction?Organization is how features are implementedControl signals, interfaces, memory technology.e.g. Is there a hardware multiply unit or is it done byrepeated addition?
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Computer Organization and Architecture - Chapter 1: IntroductionWilliam StallingsComputer Organizationand Architecture7th EditionChapter 1IntroductionArchitecture & Organization 1• Architectureisthoseattributesvisibletothe programmer —Instructionset,numberofbitsusedfordata representation,I/Omechanisms,addressing techniques. —e.g.Isthereamultiplyinstruction?• Organizationishowfeaturesareimplemented —Controlsignals,interfaces,memorytechnology. —e.g.Isthereahardwaremultiplyunitorisitdoneby repeatedaddition?Architecture & Organization 2• AllIntelx86familysharethesamebasic architecture• TheIBMSystem/370familysharethesame basicarchitecture• Thisgivescodecompatibility —Atleastbackwards• OrganizationdiffersbetweendifferentversionsDifferences in organization but not architecture leads to“families”• Differentcostandperformance• Runsamecode• Familiesmayspanyearsoftechnological advancementHierarchical Nature of Complex Systems• Eachlevelofsystemhierarchyconsistsofsetof componentsandtheirinterrelationships —OperationofcomponentsFunction —InterrelationofcomponentsStructure• Eachsuccessivelyhigherlayerdescribes simplified/moreabstractviewoflowerlevelsHierarchical Nature of Complex Systems (continued)• Breakingsystemintocomponentsormodulesforces designertodevelopadetailedunderstandingofthedata thatispassedbetweenthem• Workingwithinthehierarchy,adesignerneedstoonly concernhim/herselfwiththedetailsofhisorhermodule atthatspecificlevel• Workingwithawelldefinedsetofinputs,outputs,and functiondefinition,designerscancompletelydesigntheir modulewithoutanyknowledgeofhowrestofsystemis madeModular System DesignApplyingamodularmethodologytosystemdesignresultsin: —amoremanageableproject —quickerdesigntimebyallowingmultiplepeople withdifferingexpertisetoparticipate(althoughup frontinvestmentoftimefeelslikeadrawback) —ahigherqualitysystem —amoremaintainablesystem —increasedmodulereusabilityModular System Design (continued) Therearetwomethodstousetowarda designingamodularsystem: —Topdown —BottomupTop Down System Design• Solvingaproblembydividingthesysteminto individualfunctionsandbuildingacomponentto satisfyeachfunction.• BenefitsofTopDownDesign —Efficientuseofcomponents —Easiertomeetperformancegoalsofthesystem specification• DrawbacksofTopDownDesign —MoreexpensiveandtimeconsumingBottom Up System Design• Solvingaproblemusinganexistingsystem (e.g.,usingDLLstocreateanewapplication)• Cheaperinsmallquantities• Designtimeisreduced• PastexperiencescanbedrawnuponConcept of Black Boxes• Thisisthebuildingblockofthehierarchical systemdesign.• Ifinputs,outputs,andfunctionsarewelldefined, thedesignerdoesntneedtoknowabout anythingaboveorbelowinthesystemImplementation of components Therearethreebasicwaystoimplement asystemcomponent —Hardware(HW) —Software(SW) —Firmware(FW)Hardware• Thepermanent,physicalimplementation ofcircuitsanddevices• HardwareisrequiredforallsystemsSoftware• Theprogramscontainedinread/write memoryrangingfrommachinelanguage tohighlevellanguages• Requiresaprocessortorun(hardware dependent)Firmware• Liesbetweenhardwareandsoftware• Programs(usuallymachinecode) containedinreadonlymemoryPerformance Characteristics• Throughput/speed–HWbest;FWaverage;SW worst• DevelopmentCost–HWbest;FWaverage;SW worst• Adaptability–HWworst;FWaverage; SWbest• Reliability–HWbest;FWaverage; SWaverageStructure & Function• Structureisthewayinwhichcomponentsrelate toeachother• Functionistheoperationofindividual componentsaspartofthestructureFunction• Allcomputerfunctionsare: —Dataprocessing —Datastorage —Datamovement —ControlData Processing —Thebasicfunctionofanycomputeristoprocessdata —Describesarithmeticandlogicaloperations performedondata —Althoughendresultmaybecomplex,therearefew distincttypesofdataprocessingData Storage• Longterm —Logging —Datarecords• Shortterm —tempvariables–e.g.,buffercontainingthelastkey pressed —programcontroldata–e.g.,loopvariables ...