Chapter 7

• System life cycle has to do with the idea of developing a new system or improving upon an already existing system
• System life cycle


  1. Analysis

  2. Design

  3. Development

  4. Testing

  5. Implementation

  6. Documentation

  7. Evaluation
• Spokes and Gears want to develop an e-commerce platform to sell bikes and other accessories online due to issues with their current inventory management system
• After installing the new software, Spokes and Gears need to evaluate if it is working as intended and make necessary adjustments
• Analysis stage


  1. Research current system

  2. Identify input/output devices

  3. Identify processes

  4. Identify problems

  5. Identify user requirements

  6. Conduct interviews

  7. Examine documents
• Observation


  • Disadvantage: Workers may not perform tasks against standard procedures

  Advantage: Obtain first-hand information, better overall view of the system, inexpensive
• Interviews


  • Advantage: Opportunity for people to open up and give honest answers, allow for probing and follow-up questions

  Disadvantage: Time-consuming, relatively expensive, potential for bias and dishonesty
• Questionnaires


  • Disadvantage: Low response rate, generic and rigid questions, users tend to exaggerate responses

  Advantage: Immediate feedback, quick data analysis, inexpensive
• Examining documents


  • Disadvantage: Time-consuming, relatively expensive

  Advantage: Obtain unique information, direct observation of system operation
• Design stage


  1. File structures and data structures

  2. Input format

  3. Output format

  4. Validation routines
• Data types


  Alphanumeric, characters, text, Boolean, numeric, dates and times
• Validation routines


  1. Boolean check

  2. Data type check

  3. Presence check

  4. Length check

  5. Consistency check

  6. Range check

  7. Format check

  8. Check digits
• Verification


  Visually checking to ensure entered data matches what is displayed
• Input format


  Online form or paper-based data capture form
• Output format


  Screen layout and report layout
• Designing a system


  1. Identify the need for a structure

  2. Determine how data needs to behave within the system

  3. Identify the data types

  4. Implement validation and verification
• Input format


  How data needs to be captured
• Input format


  • Online form
  • Paper-based data capture form
• Output format


  • Screen layout - how items are arranged on the system
  • Reports layout - how the report is supposed to look
• System development life cycle

  1. Analyze the issue

  2. Design the system

  3. Develop the system

  4. Test the system
• Key things to consider during development

  • Database structure
  • Validation routines
  • Input methods
  • Testing
  • Output display
• Normal data


  Data that falls within the expected range
• Extreme data


  Data that is outside the expected range, either very high or very low
• Abnormal data


  Data that is not supposed to be within the expected range
• System implementation approaches


  1. Direct changeover

  2. Parallel running

  3. Phased implementation

  4. Pilot implementation
• Direct changeover


  • Immediate and fast
  • High risk of failure
  • Need to train users on new interface
• Parallel running


  • Lower risk of failure
  • Allows gradual staff training
  • More expensive due to running two systems
• Phased implementation


  • Low risk of failure
  • Ensures system works properly before expansion
  • Time-consuming
• Pilot implementation


  • Only one part of the company affected if new system fails
  • Longer time to implement across the whole organization
  • Possible to train staff in one area only
• Types of documentation


  • User documentation
  • Technical documentation
• User documentation


  • Limitations of the system
  • Purpose of the system
  • Software specifications
  • Tutorials on how to use the software
• Technical documentation


  • Test plan
  • Validation routines
  • User interface design
  • Flowcharts
  • System flow diagrams
• Evaluation stage


  1. Compare new system to original requirements

  2. Determine if hardware and software are working as expected

  3. Make adjustments if needed