Key Points

• Enterprise business software is designed for particular applications but always runs in the context or environment of an overall business data processing system.

• Applications thus must be integrated by testing in an actual operating environment or a virtual test version of it. In some cases, critical new software may be run in parallel for months to ensure that all situations are tested with real data.

• Successful applications software is often extended or upgraded to meet new application requirements. The new version must be tested for functionality, regressiontested for continuity, and integration-tested for conformity.

• Maintenance programmers are often less experienced than the team who wrote the software and can introduce problems.

• Taguchi Methods are well suited not only for software extension but also for software maintenance.