Zusammenfassung der Ressource
"The System
Life Cycle"
(SLC)
- Problems with new systems:
- 80% of new systems are late and over budget.
- 40% of systems are abandoned.
- 80%-90% of new systems fail to meet their target goals.
- Only 10%-20% of new systems meet their success criteria.
- If organisations follow the SLC they should
be able to avoid many of these problems
- The SLC
- Analysis
- Definition
- Investigation
- Design
- Design
- Programming
- Implementation
- Testing
- Testing
- Installation
- Documentation
- Evaluation
- Maintenence
- Maintenance
- This is a de facto
standard of how a
computer system is
created. It is a sort
of unspoken rule of
a how you should go
about making a new
system. It is the
logical way to do it.
- 1.Definition.
- Define the problem. Determine
why a new system is needed.
- 2.Investigation and Analysis.
- This decides whether a whole now IT system is needed
or whether changes can be made to the old one.
- 3.Design.
- This phase is where the detailed planning of
the system takes place in order that it may
reach is requirements and specifications.
- 4.Implementation
- Once the design stage is complete the software developers
can begin to write the code for the new system. They could
completely start from scratch writing every bit of new
code or use a template that can then be customised.
- 5.Testing
- The system must be tested in order to check that it functions
correctly. A team of beta testers will check the functionality and
'User Testers' will test whether the system is user friendly or not.
- 6.Installation
- When the system is complete, working and does everything agreed in the
design stage, then it is ready to be given to the company and installed.
- A system can be installed in
four different ways:
- 1.Direct
- 2.Parallel
- 3.Phased
- 4.Pilot
- 7.Documentation
- User Documentation:
The user is given
instructions on how
to use the system.
- On-screen documentation:
As well as paper
instructions, many modern
systems have on-screen
help that can take the
form of; Help menus, Help
pop up boxes, Video
Tutorials etc.
- Technical documentation:
These are put in by the
software developers so
that the system can be
edited if necessary. These
could be commentary in
the coding so the editer
knows what that code
does, security details etc.
- 8.Evaluation
- When the system is up and
running and all the bugs have been
ironed out, a team of anyaists will
decide whether the system meets
it's requirements and wehther it
solved the initial problem.
- 9.Maintenance
- The maintenance stage
continues the systems life.
- There are three types of maintenance:
- Corrective Maintenance.
- Adaptive maintenance
- Perfective maintanence