Software change - ESSeRE

Software change - ESSeRE

Key points

Software development and evolution should

be a single iterative process.

Lehman’s Laws describe a number of

insights into system evolution.

Three types of maintenance are bug fixing,

modifying software for a new environment

and implementing new requirements.

For custom systems, maintenance costs

usually exceed development costs.

©Ian Sommerville 2004 Software Engineering, 7th edition. Chapter 21 Slide 59