Validate the problem.
Benchmark the program.
A test script is a repository of test cases to be executed against all program revisions.
Study and debug the program to fix:
Poor program structure.
Unstructured (or poorly structured) logic.
Prior maintenance (so-called “ripple” effects.)
Dead code.
Poor or inadequate documentation.
Test the program.
Version control is a process whereby a librarian program keeps track of changes made to programs to facilitate backtracking.