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9

Software evolution

Objectives
The objectives of this chapter are to explain why software evolution is
an important part of software engineering and to describe software
evolution processes. When you have read this chapter, you will:
understand that change is inevitable if software systems are to
remain useful and that software development and evolution may
be integrated in a spiral model;
understand software evolution processes and influences on these
processes;

have learned about different types of software maintenance and
the factors that affect maintenance costs; and
understand how legacy systems can be assessed to decide
whether they should be scrapped, maintained, reengineered,
or replaced.

Contents

9.1 Evolution processes
9.2 Program evolution dynamics
9.3 Software maintenance
9.4 Legacy system management