2.6 Software maintenance  (Page 5/10)

• Determination of the scope of a change in order to plan and implement work
• Development of accurate estimates of resources needed to perform the work
• Analysis of the cost/benefits of the requested change
• Communication to others of the complexity of a given change

The severity of a problem is often used to decide how and when a problem will be fixed. The software engineer then identifies the affected components. Several potential solutions are provided and then a recommendation is made as to the best course of action.

Software designed with maintainability in mind greatly facilitates impact analysis.

Maintainability

How does one promote and follow up on maintainability issues during development? The IEEE [IEEE610.12-90] defines maintainability as the ease with which software can be maintained, enhanced, adapted, or corrected to satisfy specified requirements. ISO/IEC defines maintainability as one of the quality characteristics (ISO9126-01).

Maintainability sub-characteristics must be specified, reviewed, and controlled during the software development activities in order to reduce maintenance costs. If this is done successfully, the maintainability of the software will improve. This is often difficult to achieve because the maintainability sub-characteristics are not an important focus during the software development process. The developers are preoccupied with many other things and often disregard the maintainer’s requirements. This in turn can, and often does, result in a lack of system documentation, which is a leading cause of difficulties in program comprehension and impact analysis. It has also been observed that the presence of systematic and mature processes, techniques, and tools helps to enhance the maintainability of a system.

Management issues

Alignment with organizational objectives

Organizational objectives describe how to demonstrate the return on investment of software maintenance activities. Bennett states that “initial software development is usually project-based, with a defined time scale and budget. The main emphasis is to deliver on time and within budget to meet user needs. In contrast, software maintenance often has the objective of extending the life of software for as long as possible. In addition, it may be driven by the need to meet user demand for software updates and enhancements. In both cases, the return on investment is much less clear, so that the view at senior management level is often of a major activity consuming significant resources with no clear quantifiable benefit for the organization.”

Staffing

Staffing refers to how to attract and keep software maintenance staff. Maintenance is often not viewed as glamorous work. Deklava provides a list of staffing-related problems based on survey data. As a result, software maintenance personnel are frequently viewed as “second-class citizens” and morale therefore suffers.

Process

Software process is a set of activities, methods, practices, and transformations which people use to develop and maintain software and the associated products. At the process level, software maintenance activities share much in common with software development (for example, software configuration management is a crucial activity in both). Maintenance also requires several activities which are not found in software development. These activities present challenges to management.