A system for upgrading. There is a analysis stage it is for re-review that is to ask customer what they want to change from the preview system to the other. Or adding some touch to the new system. Then there is also design stage, to re-design the data, layout, and many more.
Verification: to prevent error
Double entry: two people or two electonics or computer
Visual check: for checking errors
Validation: to check wheather if it enters to the system or not
To solve the problem be more simple, system analysis (prelimystudy: problem definition, to make proposal).
Development and testing , implementation
Development
Finalize the file structure
Type of data
Length of each field
Field that will be key field
How the data files will be linked
4 stages:
Creating file structure
Creating validation rules
Creating input methods
Creating output formats
Testing
Ensure each one functions correctly on its own
Lead to a need to improve
Time-consuming process
Different types of testing:
Normal : 1-12
Extreme: 1 or 12
Abnormal: non numeric, coma, negative
Implementation
Changeover methods
1) direct: old system is stopped
Advantage: cost are reduce
Less likelyhood of a mal function
2) parallel running: the old and new system are running side by side for a time before the new system takes over alto.
Advantage: if system fail, there is a back up
Staff must set use to the new system
3) plot implementation: new system is introduced into one part of the company and it's performance assessed.
4) phased implementation : initially, only part of the new system is introduced. Only when it proves to satisfactorily is the next part introduced, and so on, until the old system is fully replaced.
Disadvantage: expensive
Documentation and evaluation
Documentation:
There are two type user and techmical
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