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Software Life Cycle


    Phase Possible Outcomes
    Specification - Capabilities
    - System Expectations
    - Business Analysis
    - Information Model
    Planning - Feasibility
    - Work Plan (resource/time estimates)
    - Talent Requirements
    - Organization Chart
    Analysis - Requirements
    - Testing Plans
    - Data Dictionary
    - System Archetecture
    - Data Model
    - Process Model
    - State--Transition Model
    Design - User Documentation Outline
    - Confirm Hardware
    - Interface
    - Tests
    - Programs
    - Data
    - Operation Planning
    Development - Code
    - User Documentation
    Testing - Test Code
    - Test Documentation
    - Operational Simulation
    Implementation - Distribute Code
    - Distribute Documentation
    - Train Operational Staff
    - Design Problem/Change
    - Exposure/Risk Analysis
    Maintenance - Upgrades
    - Audits
    - Problem Resolution
    - Problem/Change
    Retirement - Destruction or Preservation of Code et al.
    - Official History of System
    - Backups


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Software Life Cycle Processes

    Waterfall


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    Characteristics

    • Work proceeds from top to bottom
    • Management attempts to minimize the number of active phases
    • Each phase ends with milestone deliverables

    Advantages

    • Engineering changes are minimized
    • Forces conceptualization

    Disadvantages

    • Delays imposed to solidify milestones and from single thread
    • External changes are hard to manage

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    Phased Development


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    Characteristics

    • Requirements are grouped and satisfied at different times
    • Requirements may evolve
    • More operational data

    Advantages

    • Functions into user's hands earlier

    Disadvantages

    • Release management
    • User rejection of incomplete system

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    Prototype


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    Characteristics

    • Instead of milestones, there is fluidity
    • Analysis, Design, Development and Testing happen simultaneously
    • Multiple iterations

    Advantages

    • Shifts costs and effort lower in the cycle where they may be more acceptable
    • Users are more articulate and educated for analysis
    • Users have a system earlier but also more changes

    Disadvantages

    • More errors and deviations from intent
    • Time and cost are difficult to control

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    Throwaway Prototype


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    Characteristics

    • Like Waterfall methodology, only problems in analysis or design cause a prototype subproject initiation. The prototypes should inform the process for completing the design or analysis phase.
    • Usually the prototyping was unplanned or at least undefined

    Advantages

    • Like Waterfall

    Disadvantages

    • Like Waterfall and Prototyping


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Example: Engineer Documents & Software Life Cycle Phase

    Phase Document Defines Traces Back To
    Specification Specification Capabilities
    Planning Planning Architecture (software components) (capabilities)
    Analysis Requirements Requirements Capabilities
    Analysis Test Plan Tests Requirements
    Design Design Software Units Requirements
    Design Test Design Tests Software Units

    Traceability

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