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Systems Analysis

The stages of systems analysis (often called the system life cycle) are

- analysis

  • a preliminary study to decide exactly what the problem is.
  • undertake a feasibility study - an investigation into whether a new system is realistic.
  • study of present system - collection of data, interview staff...

- design

  • design hardware, software specifications, data storage and methods. Design of security methods.
  • top-down design involves repeatedly breaking down the design into smaller and smaller parts.
  • evaluation criteria must be specified. These are the standards by which the success of the new system will be measured.

- development and testing

  • write new programs, prepare documentation.
  • devise a test plan which involves normal data, extreme data, invalid data and null data.
  • test and debug the system.

- implementation

  • convert to new system, install hardware and software, train staff.

- maintenance

  • monitor system and solve problems as they arise. Keeping documentation up-to-date. There may slight adjustments to make as the business changes.
  • maintenance may be...
    • perfective - to improve the performance of the system
    • adaptive - to reflect changes in the business
    • corrective - to correct errors

 

Preliminary study is done by

  • interviews
  • questionnaires
  • observation
  • read existing documentation

 

Converting to the new system may be done by:

  • direct changeover
  • parallel running
  • pilot study
  • phased conversion

 

Exercise : Systems Analysis
When a computer system needs to be installed or updated a systems analyst is called in.

Remember ADDIM

A - - a study of the problem (interviews, questionnaires, observation and reading existing documentation). Doing a feasibility study.

D - - designing data storage, hardware and software requirements.

D - - writing and testing new programs, preparing documentation

I - - switching over to the new system, installing hardware and software, training the staff.

M - - monitoring the system and solving problems as they arise.

 
(Green indicates success)