System Life Cycle
Stages of System Life Cycle
Definition
The first stage is to define the problem and find out why a new system is required
Investigation And Analysis
It is also needed for the company to figure out if it is required to make alterations by doing feasibility study
Investigation is done to figure out the problems needed to be fixed. This can be done with varying ways such as questionnaires, interviews and just by observing people doing their jobs
Additional Information on Investigation Stage
Diagrams can be used as a way to help analyze the system
Diagrams that can be used are as follow: data flow diagrams, process diagrams and system diagrams
Analysis is done when investigation have finished. The analysis phase is where alternative solutions can be figured out.
Design
This stage is where the analyst will create designs.
Things that are designed
The screen layout is designed
The error messages are written
The way that you will navigate from one page to another is defined
The menu buttons are chosen
The font style, size and colour are picked
How data will be dealt with is specified
What documents can be printed out
The hardware will be needed
Development
This phase is where the system starts to be written by the software programmers. They follow the requirements specification from the design stage and start to create the new system.
Main things that take place in this phase
The programmers write and test the code for the system
A team ensure that the hardware and software required to run the new system are purchased and in place.
A team of testers are assembled in readiness to test the new system. They start to write a test plan which details all of the tests that they will carry out.
Testing
A test plan will have been written whilst the system is being developed.
Once the system has been coded, it needs to be thoroughly tested by a team of testers.
Implementation
The system has now been tested and everyone is happy that it is working correctly. It now needs to be installed so that staff can use it.
There are three different ways that you can implement a new system:
Switch off the old system and switch on the new.
You run the old and new system in parallel for a time.
You run only part of the new system
Evaluation
Now that the system is up and running for real, it is important to evaluate it.
Maintenance
Once the system has been installed and is up and running, there will be a need to keep maintaining it
Over time, bugs will be discovered that weren't picked up in the testing. These will need to be fixed.