Chapter 9 - Maintenance

Abstract

Various studies have shown that from 60 to 70% of the cost of software is incurred during maintenance. Although this percentage varies considerably from project to project, it indicates that maintenance accounts for a significant portion of engineering resources throughout the life cycle of a software product. Therefore, planning how to minimize maintenance costs is an ongoing concern. This chapter highlights the planning required to address maintenance concerns in all phases of software development. Depending on the status of a product, maintenance tasks vary but these tasks are typical: eliminating errors in the application, enhancing the application in response to customer feedback, solving regression problems, for example, the application does not work on a particular system, testing the application on new processors, both previous versions in the field and new development versions, updating documentation to reflect changes in the application, and analyzing statistics and metrics collected from customers using the product. The best way to reduce maintenance work is to minimize the avoidable errors in the application. The farther along a product is in its development cycle, the higher the cost of fixing errors.