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					                                           INFORMATION SYSTEMS @ X




                                            IT Architecture




INFO420: Managing Information Technology
                                                    INFORMATION SYSTEMS @ X




     ERP on Steroids
      What was the premise made by ERP architects that has
       proved not to be true?
      What has been the major result of the initial ERP architecture
       limitations?
      How might a more flexible architectural approach help
       organizations?




INFO420: Managing Information Technology
                                                INFORMATION SYSTEMS @ X




     Objectives
      Define and discuss importance of IT architecture and
       infrastructure from management point of view.
      Describe basic forms of IT architectures
      Discuss emerging / promising architectures: SOA and Web
       Services




INFO420: Managing Information Technology
                                                                  INFORMATION SYSTEMS @ X




     Introduction
      IT architecture versus IT infrastructure
            Architecture (logical)
             > Blueprint of ‘what’ must be built – graphical models
            Infrastructure (physical)
             > Representation of ‘how’ architecture implemented (hardware, software,
               networks)
      Today, the vast majority of IT architectures are distributed
            What does this mean?
      Evolution of Distributed Systems
            Mainframe  Client-server  Web
            What do you think: evolutionary or cyclical?



INFO420: Managing Information Technology
                                                       INFORMATION SYSTEMS @ X




     Defining the Overall IT Architecture
      Helps in the management of complex information systems
      Brings order in a ‘chaotic’ environment
      Provides standards and guidelines regarding how systems
       will be developed
            “Oracle is our database platform”
            “We will develop all custom applications with Java”
            “We will employ an SOA approach for all new applications”
      Must provide support to business strategy
            Needs to keep pace with business change (or anticipate it)
      Chief Technology Officer at the helm
            Sometimes called chief architect



INFO420: Managing Information Technology
                                           INFORMATION SYSTEMS @ X

   Enterprise IT Architecture Framework


  Architecture
   represented
   as a series of
   graphical
   models
  Zachman
   framework




INFO420: Managing Information Technology
                                                             INFORMATION SYSTEMS @ X




     Today’s IT architectures are distributed
      Degree to which a system is distributed is dependent on:
            Where the processing is done
             >   Share the work across multiple computers
             >   Inter-transactional
             >   Intra-transaction
             >   Requires system interoperability
            How processors and other devices are interconnected
             > Redundancy (at least one alternative route)
            Where the information is stored
             > Distributed databases
            What rules or standards are used
             > Need system-wide rules




INFO420: Managing Information Technology
                                                INFORMATION SYSTEMS @ X




     Modern IT Architectures
        Client-server Systems
        Internet-Based Computing
        Services Oriented Architecture (SOA)
        Web Services




INFO420: Managing Information Technology
                                                     INFORMATION SYSTEMS @ X




     Client Server Computing
      Share the work among multiple clients and servers.
             (P)resentation
             (A)pplication
             (D)ata
      Clients: make requests
      Servers: respond to requests, provide various types of
       services.
      Thin client (weak): refers to a client with relatively few
       computing capabilities and most of data processing will be
       done at the server.
      Fat client (powerful): refers to a client with greater computing
       capabilities.
      2, 3 and 4 tier (internet-based application) models
INFO420: Managing Information Technology
                                                      INFORMATION SYSTEMS @ X




     Client Server Computing – Two Tier (Web browsing)




       Web Browsing: The client in this architecture is ‘thin’ most of
                 the processing happens on the server

INFO420: Managing Information Technology
                                                                      INFORMATION SYSTEMS @ X




     Client Server Computing – Three Tier

                                                             “The face”
                                                    User interface (Presentation)
                            Client                    Some basic processing
                                                 Makes requests of application server
                                                            Usually a PC


                                                             “The brains”
                          Application                 Logic, workflow, decisions
                            Server           Serves requests of client; makes requests of
                                                           database server


                                                             “The brawn”
                           Database        Manages data (query, add, delete, change) and data
                            Server                              security
                                           Responds to requests from the application server




INFO420: Managing Information Technology
                                                   INFORMATION SYSTEMS @ X




    Client Server Computing - Benefits
    Scalable: Work shared across many clients and servers. If
     more processing power needed, plug in another server
    Reliable: Many servers: If one fails, work can be shifted to
     others
    Maintainable: Support and maintenance costs are less –
     servers can be replaced over time




INFO420: Managing Information Technology
                                                   INFORMATION SYSTEMS @ X




     Client Server Computing - Drawbacks
      Very complex to administer
      Many more ‘points of failure’
      Security: more ways system can be hacked.
      Performance: Can be difficult to locate and fix performance
       issues – many potential bottlenecks.




INFO420: Managing Information Technology
                                                   INFORMATION SYSTEMS @ X




     Internet-Based Computing
      Extension of client-server (via Internet)
      Different models
            Server based
            Peer to peer




INFO420: Managing Information Technology
                                                                         INFORMATION SYSTEMS @ X

 Client Server Computing – Four Tier (Web-based
 applications)

                      Thin Client (Browser)           Presentation only: Web browser

                                                 ‘Brokers’ requests between client and application
                          Web Server                                    server
                                                    e.g., renders results in HTML so they can be
                                                               displayed on a browser.

                                                                “The brains”
                          Application                    Logic, workflow, decisions
                            Server              Serves requests of client; makes requests of
                                                              database server


                                                                “The brawn”
                           Database           Manages data (query, add, delete, change) and data
                            Server                                 security
                                              Responds to requests from the application server



INFO420: Managing Information Technology
                                                   INFORMATION SYSTEMS @ X




     Internet-Based Computing: Server-based
      Mobile workers laptops and PDAs (Blackberrys)
            Software update difficulties
            Data security
      Applications and sensitive data reside on server
            e.g. Citrix Server (remote desktop)
      Easier management
      Lower cost




INFO420: Managing Information Technology
                                                 INFORMATION SYSTEMS @ X

     IBM, Nokia and Sabre Project: Pervasive
     Computing
      What do you think ‘pervasive computing’ is?
      What are the key benefits of this application?
      What are the key challenges that need to be considered?




INFO420: Managing Information Technology
                                                 INFORMATION SYSTEMS @ X




     Internet-Based Computing: Peer to Peer
      Task distributed to wide number of computers (peers)
       connected over the Internet
            SETI at Home
            Limewire
      Share costs
      Whole > sum of parts




INFO420: Managing Information Technology
                                                          INFORMATION SYSTEMS @ X




     Service Oriented Architecture (SOA)
      The following figure illustrates a basic service-oriented
       architecture.




      Both the sender and receiver know how to communicate, but don’t
       care about the internal workings of each other
      Services could be within a company, or you could access services
       from another organization – they just need to agreed on how
       services will communicate



INFO420: Managing Information Technology
                                                                      INFORMATION SYSTEMS @ X




     SOA - Example
      Build a supply chain management system out of existing
       ‘components’




                            New Supply Chain Management Application




           Oracle Manufacturing                                   Another Company’s
                  System                                        inventory system (SAP)




INFO420: Managing Information Technology
                                                    INFORMATION SYSTEMS @ X




     Web services
      Second-generation Internet-based distributed system
      A form of Services Oriented Architecture based on WWW and
       Internet standards
            Software (XML)
            Communication protocol (SOAP, HTTP, TCP/IP)




INFO420: Managing Information Technology
                                                      INFORMATION SYSTEMS @ X




     Significance of Web Services
      How does it impact business and work?
            From proprietary IT architecture to Web Services based on
             openness of Internet
             > Agility
             > Cost avoidance
             > Pay only for needed functionality




INFO420: Managing Information Technology
                                                           INFORMATION SYSTEMS @ X




     Today’s students
      http://www.youtube.com/watch?v=dGCJ46vyR9o
      Form small groups:
             What are the implications for IT architecture for institutions
              like StFX?




INFO420: Managing Information Technology

				
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