Objectives

Understand Corrective, Perfective and Preventive maintenance

Discuss the general concepts of software configuration management

Corrective maintenance procedureCritical incident reportAnalysis of problemIdentification of solutionCorrection of softwareDocumentation of updates

Critical incident report format

Date & time of incidentName of the person who filed the

reportDescription of the problem Probable causeCorrective action taken

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

Types of errors

System errors–due to hardware or system software

failures–due to stretching of system

capabilities–solution is comprehensive stress

testing

Types of errors

Operations errors

–due to errors by computer department staff

–solution is clear instructions, standard operating procedures and frequent monitoring

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

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.

Common efficiency methods

Reading a block of records rather than a single record

Storing calculated values and reusing them

Improving loops in a programUsing default values

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.

Software configuration management

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

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.

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