computing resource paradigms cs3353. computing resource paradigms centralized computing distributed...
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Computing Resource ParadigmsCS3353
Computing Resource ParadigmsCentralized ComputingDistributed Computing
Early Centralized Computing ParadigmCharacterized by one central computer.Housed in a limited access, climate controlled room.A shared resource users connect through dumb-terminals.Limited interactive access.Jobs are submitted through batch job-queues.
Centralized ComputingThere remain highly specialized computer systems of this type:Supercomputers designed for special resource intensive problem solving.
Cray T3E/512-PE Supercomputer Mainframe
Centralized Computing AdvantagesIdeal for maintaining a high level of security.Climate controlled environment is equipment friendly.Reduces maintenance costs.
Distributed ParadigmDemand driven by departments wanting access to more computing resources beyond the confines of centrally controlled systems.Unix becomes a popular operating system for this paradigm.HP, Sun, SGI, and others ride this wave during the 1980s.
Client-ServerThe spread of networks and low cost network hardware led to the client-server computing paradigm. This successfully merges the two central and distributed paradigms.Computers are interconnected by a network. The computers are classified as either clients or servers in the network.
ServerA powerful computer configured to provide services to other computers within a computing system environment.Example Services:DiskPrinterApplicationE-mailetc
ServerThe server is typically a powerful computer configured with:Fast processors (1 or more)Fast and reliable disk storageMemory rich
ServerCentral location for the server allows ease of maintenance and high levels of security.Simplifying the maintenance of the system helps control costs.Small operations (businesses) can put a powerful central computing system in a small room. There it can be relatively secure and easy to maintain.
Behind the Server Rack
The ClientA client is configured to access specific services within the boundary of the defined computing system environment.Client classifications:Fat client: fully functional workstationThin client: a dumb terminal or graphical displayHybrid client: between thin and fat.
ClientFat clients are fully functional computers with local storage and computing capability. Thin clients rely on a server to provide storage and computing resources. Characterized as diskless and without a processor.Hybrid clients provide some computing resources independent of a server; storage is provided by a server.
ClientThin/Hybrid clients can cost less than fat-clients to purchase and maintain when carefully chosen.Work well for:public access areashigh security environmentsWhen full function workstations are unnecessary.Reduces maintenance for cost conscious businesses.