9.2.5 Maintaining

Question 1

What does maintaining code refer to?

Answer 1

1. Correcting bugs
2. Improving code efficiency (eg speed, reduced memory usage etc)
3. Adding features

Question 2

List reasons for maintaining software.

Answer 2

1. Bug fixes
2. Support for new hardware or software
3. Support for new operating systems
4. Legal or regulatory changes
5. Additional features

Question 3

How does intrinsic documentation contribute to the maintenance of code?

Answer 3

Good intrinsic documentation makes it easier to modify in newer versions as the purpose of different elements of code can be easily understood not just by the original developer.

Question 4

What is a patch and how is it used in the maintenance of software.

Answer 4

Users need a way to update their software when changes are made.

A patch is an executable file that modifies the existing code in an installation to make these changes.

The alternative would be to have users completely reinstall the updated program.

Question 5

When maintaining code, how would developers locate the section of code to be altered?

Answer 5

• Use of systems models to identify modules that require changes (eg structure charts, data flow diagrams).
• Once located, developers would use documentation like IPO diagrams, data dictionaries and other internal documentation to understand the code they need to modify.

Question 6

What are some examples of changes that developers might make to the source code?

Answer 6

1. Changing modules or subroutines for additional functionality
2. Changing the number or type of parameters and return values
3. Changing data types or data structures.
4. Making modifications to the user interface.

Question 7

Discuss the importance of testing when maintaining source code.

Answer 7

• A modular approach will enable any changes made to be tested at the module level, using existing or additional test data.
• However, if there have been changes to data types, parameters and return values, then higher level modules/subroutines that use these would need to be updated.