Chapter 15 Systems Development I. Systems Development Life Cycle (SDLC)

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Chapter 15 Systems DevelopmentI. Systems
Development Life Cycle (SDLC)
Planning Analysis Design Implementation Support
How does the IS fit in firms plans? Investigation Requirements to functions Training Maintenance
How does the IS fit in firms plans? Feasibility Evaluate alternatives Conversion User support
Requirements definition Programming
Testing
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1. Planning (Chapter 14)2. Analysis

• Initial investigation
• Talk to users is there a real problem?
• Submit preliminary report
• Detailed investigation
• Feasibility study
• Technical
• Economic
• Operational
• Requirements definition
• What does the system need to do so it will
  fulfill its goals?
• Collection of information from users
• Interviews
• Questionnaires
• Examination of documents
• On-the-job observation

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Economic Feasibility Cost/Benefit Analysis
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3. Design Design Phase I

• Requirements Functions Components
• Outputs Processing Inputs
• Typical components
• Input files, procedures, output files, user
  dialog (GUI), interfaces
• Graphical tools used to model systems
• Flowcharts
• Data flow diagrams
• Unified modeling language (UML)

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Design Phase II

• Evaluate alternatives
• If a LAN is required, then what shape, what
  media?
• Select programming language
• Components logical design versus physical design
• Logical design includes specifications of input
  (design view) and output files (report design)
• Physical design involves specifications related
  to the hardware components required of the system
  (e.g., 16 pcs with 4.8 GHz cpus and 80 GB hard
  drives, fiber optic cable with 8 mbps capacity)

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Design Phase III

• Construction
• This is where the programming is done
• Modular construction modular testing
• Evidence of modules in Windows applications
• Systems Testing
• Once modules are completed system is assembled
• Systems testing where you purposely try to make
  the system fail often rushed or omitted
• Role of business people

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Examples of Designer Specifications

• OUTPUT
• MEDIUM CONTENT TIMING
• INPUT
• ORIGINS FLOW DATA ENTRY
• USER INTERFACE
• SIMPLICITY EFFICIENCY LOGIC
• FEEDBACK ERRORS
• DATABASE DESIGN
• LOGICAL DATA RELATIONS
• VOLUME, SPEED REQUIREMENTS
• FILE ORGANIZATION DESIGN
• RECORD SPECIFICATIONS

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Examples of Designer Specifications

• PROCESSING
• COMPUTATIONS
• PROGRAM MODULES
• REQUIRED REPORTS
• TIMING OF OUTPUTS
• MANUAL PROCEDURES
• WHAT ACTIVITIES
• WHO PERFORMS THEM
• WHO PERFORMS THEM
• HOW
• WHERE

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4. Implementation

• Training
• Possible methods (in class on site, Web, distance
  learning, CDs, in class off site), intranet
• Coordination with conversion
• Conversion
• Parallel Conversion
• Phased Conversion
• Cut over (Cold Turkey) Conversion
• Pilot Conversion

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Conversion Strategies
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5. Support

• Maintenance
• Post-implementation debugging
• System changes and additions
• Support
• Assist users and ensure that the system is
  operated in a satisfactory manner
• Importance of good documentation in this phase
• Paper books/manuals
• Electronic documents
• Commentary within programs
• Longest of SDLC phases

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Pros and Cons of SDLC

• Pros
• Thorough analysis and design
• Well-defined phases to track progress
• Tangible outputs at the end of each phase
• Works well if requirements are well understood
• Only reasonable method in large complex systems
• Cons
• Lengthy process
• Requirements are frozen and difficult to change
• Requires significant resources in time/people

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II. Prototyping

• Systems developed using an iterative process
• Purpose is to develop a working model as quickly
  as possible, which can be revised
• Requirements determined in an iterative manner
• Significantly shortens systems development
  backlog
• Can increase risk of incompatibility and other
  unforeseen mishaps
• Prototyping is often used in conjunction with
  SDLC

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Prototyping
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Prototyping
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III. Agile Methods

• These methods try to deliver a useful IS to the
  user as quickly as possible without compromising
  features
• In SDLC users are required to sign a contract
  agreeing on system requirements. This freezes
  the requirements
• Characteristics of agile methods
• Produce demo system in weeks
• Get feedback from users
• Design for simplicity so changes are quick and
  easy
• Test constantly
• Communicate with users informally and frequently
• Encourage users to explain how they will use the
  system

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IV. Systems Development Led by End Users

• Motivation
• Agile methods got users more involved but they
  did not lead projects SDLU promotes the idea
  that better systems result when systems projects
  are lead by users
• Joint application development (JAD) an example of
  SDLU
• Planning phase determines requirements in a
  workshop setting led by a user top management
  presence similar to analysis from SDLC
• Design phase determines how the system will
  work in a workshop setting outputs include data
  flow diagrams, design views of tables, screen
  designs, etc. lots of prototyping is used

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Why End User Development

• Backlog of MIS project
• Available powerful and easy to use software tools
• Suitable for small projects that involves users
  expertise.
• Suitable for projects that support one-time
  decision-making.
• Suitable for projects that can be completed by
  using off-shelf software.

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V. Systems Integration

• Takes a look at the information needs of an
  entire organization (or a major division)
• Analysts integrate existing systems so that
• Data can flow more easily among business units.
• Users can access different types of data via a
  single interface.
• Examples of systems integration
• Linking existing systems to Web sites
• Linking databases to Web sites
• Linking systems between two or more organizations

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VI. Ethical and Societal IssuesShould IS
Professionals Be Certified?

• Malfunctioning ISs
• Faulty systems may wreak havoc, causing financial
  damage or even death
• Should IS professionals be certified based on the
  high investment and risk involved in their work?

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Ethical and Societal IssuesShould IS
Professionals Be Certified?

• Certification Pros
• Protect potential employers
• Protect clients of consultants
• Fewer software-related failures
• Certification Cons
• Difficult to measure software competence
• May create a closed shop decreased
  competition, decreased incentive to improve
  skills