Systems Development

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Systems Development
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Motivation

• If you are in business, youre going to be
  involved in _____ _____
• Building good software applications requires
  involvement by the END USER--the you, friend
• A PHILOSOPHY--TI
• We will reuse before we will buy and we will buy
  before we will create using 3 or 4GLs

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Problems with software development

• It takes too long
• It costs too much
• It doesnt deliver the required functionality
• Over 70 of SD projects fail!!!

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Concept of Systems Development Life Cycle (SDLC)

• Definition of SDLC
• Stages of SDLC
• Traditional versus modern SDLCs

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Systems Development Life Cycle (SDLC)

• An SDLC represents a set of general categories
  that show the major steps, over time, of an
  information systems development project.

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An Eight-Stage SDLC

• Project initiation
• Feasibility study
• Logical analysis and design
• Acquisition and development
• Implementation
• Operation
• Post-audit evaluation
• Maintenance

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SDLC
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Whats Missing here?

• Testing--up to 40 of the total development time
• your book has nothing to say about it at
  all--SHAME
• We should also note that roughly 80 of ISD
  budgets are spent on maintenance
• This includes fixing bugs
• Changing interfaces, structure
• Enhancements

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Project Initiation

• Functional Manager
• Formal planning process
• IS organization

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Feasibility Studies

• Technology
• Economics
• Organizational factors
• Legal, ethical, and other constraints
• But not the time-frame for development

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Logical Analysis and Design

• Determine the systems functions
• How will it accomplish those functions
• Logical design
• Physical design / technical design

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Logical Design

• Generic IS functions input, output, and storage
• Modeling tools DFDs, ERDs
• Data Flow Diagrams
• Entity-Relation Diagrams
• User involvement

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Implementation

• Parallel conversion
• Direct cut-over
• The most risky
• Pilot conversion
• May be implemented in a subset of locations
• Phased

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Traditional versus Modern SDLC

• Minimal overhead
• Flexibility and responsiveness
• Concurrent tasks
• Focused analysis

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Methods for Complex or Quickly Needed Systems

• Prototyping
• Rapid Application Development (RAD)
• Object-Oriented Development (OOD)
• End-User Development (EUD)

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Prototyping

• The prototyping approach to systems development
  is, in many ways, the very opposite of an
  old-style SDLC. The focus of prototyping is to
  develop something quickly from the users initial
  set of requirements. Then refine and extend it
  based on the users requirements, which are
  identified by using the prototype.

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More on Prototyping

• May use a 4GL to prototype
• Best when user requirements are not well-defined
• Helps developers get the user interface right
• Finalized code is then written in a 3GL--C, C,
  etc.
• Also known as EVOLUTIONARY development

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Rapid Application Development

• Rapid Application Development (RAD)
  methodologies and tools have capabilities to meet
  the demands of the new environment.

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Components and Capabilities of RAD

• Uses a 4GL--Visual Basic, PowerBuilder, Delphi
• Uses a client-server architecture
• GUI development environment
• the ability to drag-and -drop components into an
  application
• Reusable components
• Code generator
• Programming language

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Object-Oriented Development

• Encapsulation
• Inheritance
• Plug-and-play landscape
• Polymorphism--the ability to send the same
  message to several different receivers and have
  the message trigger the correct service

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Object-Oriented Development

• Procedures (functions, subroutines) are called
  methods
• Generic objects are called classes
• Specific objects are called instances

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Object-Oriented DevelopmentBenefits

• Reduces complexity of systems development
• Systems are quicker and easier to build and
  maintain
• Improves productivity
• Objects may be reused

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Object-Oriented DevelopmentBenefits

• Systems are more flexible
• Allows analysis to think in real world terms
• Ideal for Web development

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End-User DevelopmentTrends

• END-USERS ARE DOING MORE SOFTWARE DEVELOPMENT
• Increasingly powerful desktop hardware
• Declining hardware costs
• Increasingly diverse software capabilities
• Increasingly computer-literate population
• Backlog of centralized IS projects (36 or more
  months)

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More End-User Development(EUD) Trends

• Development speed
• Business orientation
• Small applications
• Control
• Apparent cost savings

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EUD Problems

• Additional spending
• Hardware
• Software
• Training
• Support
• Neglecting other duties

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More EUD Problems

• Limited managerial technical skills
• Documentation
• Security

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EUD Solutions

• Auditing EUD programs
• Dividing computing responsibilities

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Third Party Software

• Application software packages
• Outsourcing
• Enterprise software
• SAP, Computer Associates, Oracle,

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Who is the largest software company?

• IBM?
• Microsoft?
• SAP?
• Oracle?
• Computer Associates?
• Novell?
• You will have to know for the exam

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Internet Development

• Web pages are primarily coded in HTML
• Java scripts are used to produce the animation
  boxes

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Development Tools

• Database creation tools
• 4GLs
• CASE tools--broadest support for the SDLC (the
  systems development process)
• Computer-Aided Software Engineering (Sterlings
  COOL GEN series)
• Object-oriented tools like FORTE, Optima
• Testing tools
• Documentation tools

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Acquiring New Systems--Outline

• Desirable outcomes and implementation issues
• Managerial considerations

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Desirable Outcomes and Implementation Issues

• On-time
• On-budget
• Full functionality
• User acceptance
• Favorable costs-to-benefits ratio

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More Desirable Outcomes and Implementation Issues

• Low maintenance
• Scalability
• Integration with other systems
• Minimal negative cross impacts
• Reusability

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Capability Maturity Model

• Developed by the SEI at Carnegie Mellon
• A way to assess the maturity of any software
  process, such as development
• Initial
• Repeatable
• Defined
• Managed
• Optimizing

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Management Considerations

• Traditional SDLC methodology
• Prototyping
• Rapid Application Development (RAD)
• Object-Oriented Development (OOD)
• End-User Development (EUD)
• Purchasing or outsourcing

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System Development Issues

• Internet and intranet applications
• JAVA
• CASE tools
• IS-9000
• Project planning

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Managerial Issues

• Importance
• Building inter-organizational and international
  information systems
• Ethical and legal issues
• User involvement
• Traditional approaches vs. prototyping

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Managerial Issues

• Tool use by developers
• Quality assurance vs. schedules
• Behavior problems
• Perpetual development