Waterfall Model

Waterfall Model

Features
1. Sequence of distinct phases
2. 1 stage must be finished before moving onto a next phase
3. Deliverables at end of each stage used to ensure progress
4. If error is found during a stage then previous stages may need to be reworked
Stages
1. Analysis
  1. Help Systems Analyst define requirements
  2. Questionnaire
  3. Observation
  4. Interview
  5. Document Inspection
  6. Discover the data, volume of data, information, users & roles, problems with current system
2. Design
  1. Solution defined
  2. Data to be processed specified
  3. Input, Processes & Format of Output defined
  4. Hardware & Software requirements
  5. Testing strategies defined
3. Development & Testing
  1. Unit Testing
    1. Testing each field, button etc. for validation
    2. Person who wrote code
  2. Integration Testing
    1. All code functions together
    2. Construction Team
  3. System Testing
    1. Actual data if used in real situation
    2. Under supervision of Systems Analyst
  4. Types of Test Data
    1. Extreme
      1. On Boundary
    2. Valid/ Normal
      1. Within Boundaries
    3. Exceptional
      1. Doesn't follow rules but valid e.g. 29th February
    4. Invalid/ Erroneous
      1. Not Acceptable
4. Implementation
  1. Parallel
    1. Old & New side by side
    2. Safer
    3. More work
  2. Phased
    1. Part I complete before Part 2
    2. Safer
    3. Long
  3. Direct
    1. New system starts on set day
    2. Faster
    3. Stressful, No fall back
  4. Pilot
    1. Installed in one branch
    2. Train other staff, identify problems
    3. Takes Time
5. Review & Maintenance
  1. Corrective
    1. Small issues after installation
  2. Adaptive
    1. Due to external factors e.g. VAT change
  3. Perfective
    1. System in place for some time but some small tweaks identified

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	Created by scott.dowle almost 11 years ago