The Systems Life Cycle

The Systems Life Cycle

GCSE ICT - Computer System

A computer system can be used for many purposes and across a large range of industries, including transport, retail, factory production, medicine and farming.There are four main stages in setting up a new system. They are 1.) Analysis 2.) Design 3.) Implementation and 4.) Evaluation.

1 Analysis involves assessing the exact function of the system, who it will be used by, where it will need to be installed etc. There may already be a system in place that can be improved upon, in which case the analysis will involve working out what already works well and which parts of the existing system need to be replaced.

A systems analyst may need to

  • Observe the staff at work
  • Talk to staff about what they do and what they need
  • Put together a questionnaire for staff to complete

The feasibility study will require the analysts to answer some practical questions.

  • Can this system be realistically put into operation given the time and budget available?
  • Will it be cost effective? In other words, will it save more money that it costs?

2 Design – If the answers to these questions are yes, and the decision makers have agreed to it, then the design process will begin. The requirements specification will need to state what hardware and software is required, what information will need to be fed into the system, what processing needs to take place and what information will need to be fed back to the system user.

Testing is an important part of the design process. The system will normally be tested with three different types of data.

  • Normal data – the kind of data the system will usually have to deal with
  • Extreme data – data which hovers between normal and extreme data
  • Extreme data – (wrong data) which should prompt the system to tell the user that invalid data has been input.

3 Implementation – This is when the system is actually put into operation, although to begin with it may be phased in, or operated alongside the existing system (parallel running) in case things go wrong. Of course staff will have to be trained on the new system and a number of user documents will be produced, including a user and installation guide.

4 Evaluation – As with all new designs there are almost certainly going to be teething problems and so problems will need to be monitored and addressed. Further testing, discussion with system users and reimplementation may need to occur.