1. Objectives
Understand Corrective, Perfective and Preventive maintenance
Discuss the general concepts of software configuration management

2. Corrective maintenance procedure
Critical incident report
Analysis of problem
Identification of solution
Correction of software
Documentation of updates

3. Critical incident report format
Date & time of incident
Name of the person who filed the report
Description of the problem
Probable cause
Corrective action taken

4. Types of errors Program logic errors
due to faulty understanding of system requirements
due to not considering all possible options
solution is more time on analysis & requirement study

5. Types of errors System errors
due to hardware or system software failures
due to stretching of system capabilities
solution is comprehensive stress testing

6. Types of errors Operations errors
due to errors by computer department staff
solution is clear instructions, standard operating procedures and frequent monitoring

7. Types of errors User errors
due to errors by users while working on the system
solution is detailed user manuals, extensive training and on-line help facility

8. Perfective maintenance
Perfective maintenance deals not with correction of problems but with improving the efficiency of a running program.
By improving 5% of the code, a 20% improvement in the program’s run time can be realized.

9. Common efficiency methods
Reading a block of records rather than a single record
Storing calculated values and reusing them
Improving loops in a program
Using default values

10. Preventive maintenance
Preventive maintenance or software reengineering is required to modify computer programs so that they can be easy to maintain i.e. easy to correct, adapt or enhance.

11. Software configuration management
Software configuration management is the art of identifying, organizing and controlling modifications to the software being developed by a programming team

12. Software configuration
All items comprising the information produced as part of the software process are collectively known as software configuration
For example, software programs, user manuals, payroll data are all software configuration items.

13. What is a baseline?
The IEEE standard defines baseline as a specification or a product that has been formally reviewed and agreed upon that thereafter serves as a basis for further redevelopment and that can be changed only through formal change control procedures