Maintenance of systems

Maintenance of systems

1. corrective

   • errors are found in the system
   • errors realised when using it normally
   • must be corrected to make it usable

2. perfective

   • system is satisfactory
   • room for improvement
   • software improved to better performance

3. adaptive

   • parameters might change
     • VAT rate might change
   • new requirements
     • d to be updated to do the job
   • new ideas
     • betters the program for the customer