What prompts a new system?

Requirements analysis

Gathering details about the current system will involve:

• Interviewing staff at different levels
  from end-users to senior management
• Examining current business and systems documents and output
  may include current order documents, computer systems procedures and reports used by operations and senior management
• Sending out questionnaires
  the questions have to be carefully constructed to elicit unambiguous answers
• Observation of current procedures
  by spending time in various departments; a time and motion study can show where procedures could be more efficient, or to detect bottlenecks

System design

Specifies the following aspects of a system:

• The hardware platform
  which type of computer, network capabilities, input, storage and output devices
• The software
  programming language, package or database
• The outputs
  report layouts and screen designs
• The inputs
  documents, screen layouts, validation procedures
• The user interface
  how users will interact with the computer system
• The modular design
  of each program in the application
• The test plan and test data
• Conversion plan
  how the new system is to be implemented
• Documentation
  including systems and operations documentation. Later, a user manual will be produced

Successful implementation

What are the criteria for judging the success of a system? Here are some possible measures:

• High level of use
  Is the new system actually used?
• High level of user satisfaction
  Do users like the system?
• Accomplishment of original objectives
  Have they been satisfactorily achieved?
• Appropriate nature of use
  Do users really know how to use it?
• Institutionalisation of the system
  A successful system will be taken on board enthusiastically by users and used in new and changing ways, evolving to meet new demands

Methods of conversion

• Direct changeover
  The user stops using the old system one day and starts using the new system the next — usually over a weekend or during a slack period
• Parallel conversion
  The old system continues alongside the new system for a few weeks or months
• Phased conversion
  Used with larger systems that can be broken down into individual modules that can be implemented separately at different times
• Pilot conversion
  New system will first be used by only a portion of the organisation, for example at one branch or factory

System maintenance

• Perfective maintenance
  implies that while the system runs satisfactorily, there is still room for improvement
• Adaptive maintenance
  All systems will need to adapt to changing needs within a company
• Corrective maintenance
  Problems frequently surface after a system has been in use for a short time, however thoroughly it was tested

Prototyping

The waterfall model of the system life cycle doesn’t allow for modifications to the design.

Benefits of prototyping

• Misunderstandings between software developers and users can be identified;
• Missing functions may be detected;
• Incomplete or inconsistent user requirements may be detected;
• A prototype version will be quickly available to demonstrate the feasibility to management;
• The prototype can sometimes be used for training before the final system is delivered.

The current system may no longer be suitable for its purpose

Technological developments may have made the current system redundant or outdated

The current system may be too inflexible or expensive to maintain