1ISM 50 - Business Information SystemsLecture 10Instructor: John MusacchioUC Santa CruzOctober 25, 20102Representation needs to be standardizedInformationDataInformationDataCommunicate data toanother user or organizationIf the representationis not standardized, theinformation is garbled!Slide adapted from slides for Understanding Networked ApplicationsBy David G Messerschmitt. Copyright 2000. See copyright notice3RegenerationMake a precise copy of the data (copy bit by bit)If you know the representation, this is equivalent to making a precise copy of the informationEach such precise copy is called a generationprocess is called regenerationSlide adapted from slides for Understanding Networked ApplicationsBy David G Messerschmitt. Copyright 2000. See copyright notice4Replication of information0101011010111101011011010010110000001101010111101110101010111010101010110101111010110110100101100000011010101121011101010101110101010101101011110101101101001011000000110101011110111010101011101010101011010111101011011010010110000001101010112101110101010111010101010110101111010110110100101100000011010101111011101010101110101010101101011110101101101001011000000110101011210111010101011101010101011010111101011011010010110000001101010111101110101010111010101010110101111010110110100101100000011010101121011101010101110101Anything that can be regenerated can be replicated any number of timesThis is a blessing and a curse5Analog information cannot be regeneratedAnalog information can be copied, but not regeneratedWe will never know exactly what the original of this Rembrandt looked like6Discrete information can be regeneratedRegeneration can preserve data (but not its original physical form)Regeneration is possible for information represented digitally (which is tolerant of physical deterioration)0 + noise Ô 01 + noise Ô 17Replication of information requires knowledge of representationInformationDataInformationDataReplicationReplication of informationalso presumes knowledge ofits representationReplication preserves the integrityof the data, but that is not sufficientSlide adapted from slides for Understanding Networked ApplicationsBy David G Messerschmitt. Copyright 2000. See copyright notice8ImplicationsDigitally represented information can be preserved over time or distance digital librarydigital telephonyReplication of data is easy and cheap9Implications (cont)Replication requires knowledge of the structure and interpretationStandardization or some other meansExtreme supply economies of scaleYou can give away or sell and still retainPiracy relatively easy10ArchitecturebyDavid G. Messerschmitt11Copyright notice©Copyright David G. Messerschmitt, 2000. This material may be used, copied, and distributed freely for educational purposes as long as this copyright notice remains attached. It cannot be used for any commercial purpose without the written permission of the author.Slide adapted from slides for Understanding Networked ApplicationsBy David G Messerschmitt. Copyright 2000. See copyright notice12What is Architecture?How do you architect a solution?13A system is decomposed into interacting subsystemsEach subsystem may have a similar internal decompositionArchitectureSlide adapted from slides for Understanding Networked ApplicationsBy David G Messerschmitt. Copyright 2000. See copyright notice14Three elements of architectureDecompositionFunctionalityInteractionOrganizationResponsibilityCooperationSlide adapted from slides for Understanding Networked ApplicationsBy David G Messerschmitt. Copyright 2000. See copyright notice15System examplesLets quickly look at some system decomposition examplesQuick tour of information technology systems16Time sharingASCII terminal(no graphics)Point-to-point wire (no network)Mainframe (database and application server)17Two-tier client/serverLocal-area networkServer/Mainframe18Three-tier client/serverApplicationserverEnterprisedata serverClient19System integrationArchitecture->subsystem implementation -> system integrationBring together subsystems and make them cooperate properlyRrequires testingMay require modifications to architecture and/or subsystem implementation20EmergenceEmergence -- capabilities that arise purely from that interaction (desired or not)e.g. airplane flies, but subsystems cant21Why system decomposition?Divide and conquer approach to containing complexityReuseConsonant with industry structure (unless system is to be supplied by one company)Others?22Networked computing infrastructurebyDavid G. Messerschmitt23LayeringExisting layersElaboration or specializationServices24Example of Layering: networkingPhysicalLinkNetworkTransportApplicationMessagesPacketsFramesBitsSignals25Software LayeringApplicationMiddlewareOperating System26Operating system functionsGraphical user interface (client only)Hide details of equipment from the applicationMultitaskingResource managementProcessing, memory, storage, etcetc27Middleware FunctionsCapabilities that can be shared by many applications, but that is not part of OSExample: Database Management System (DBMS)Hide details of OS from applicationJava Virtual MachineMore purposes well talk about later.28Whats a database?DatabaseFile with specified structureExample: relational table29Year City Accommodation Tourists2002 Oakley Bed&Breakfast 142002 Oakley Resort 1902002 Oakland Bed&Breakfast 3402002 Oakland Resort 2302002 Berkeley Camping 1200002002 Berkeley Bed&Breakfast 34502002 Berkeley Resort 3908002002 Albany Camping 87902002 Albany Bed&Breakfast 32402003 Oakley Bed&Breakfast 552003 Oakley Resort 3202003 Oakland Bed&Breakfast 2802003 Oakland Resort 2102003 Berkeley Camping 1158002003 Berkeley Bed&Breakfast 45602003 Berkeley Resort 4190002003 Albany Camping 76502003 Albany Bed&Breakfast 6750A Database30Storage Middleware example: DBMSDatabase Management System (DBMS)Manage Multiple databasesAllow multiple applications to access common databasesImplement standard data lookup (query) functions.31The InternetbyDavid G. Messerschmitt33What is the Internet?An internet is a network of networksInterconnect standard for LANs, MANs, and WANsInternet = the major global internetA private internet is called an intranet34Client - Server Computing35Client Server ExampleClientI want to seewww.google.com Server<html><head><meta http-equiv="content-type"