Phases of the System Development Life Cycle:

1. THE REUSE-ORIENTED APPROACH PRESENTERS: ANA-STACIA BARRETT SHENELL DELPRATT Phases of the System Development Life Cycle:

2. The Nature of Maintenance • It is important to maintain a system after development. • Without good documentation maintenance of the system becomes difficult. • Maintenance comprises : • Correcting faults in the problem. • Adapting the system to changing operating environment. • Adapting the system to changes in original requirements. • The new system is a modified version of the old system.

3. The Reuse- Oriented Approach

4. The Quick Fix Module • This represents an abstraction of the typical approach to software maintenance. • The approach taken by this module is: • Take the existing system, usually the source code. • Make the necessary changes to the code and the accompanying documentation. • Recompile the system as a new version. • Used to change some internal component like an error correction. • Viewed as reuse oriented because it creates a new system by reusing or simply modifying the old.

5. The Quick-fix Module

6. The Interactive Enhancement Module • This is an evolutionary module used in cases where: • Development in environments where the complete requirements of the system were not fully understood. • The developer did not know how to build the full system. • The approach taken by this module is: • Starts with the existing system’s requirements, design, code, test and analysis documents. • Modifies the set of documents, starting with the highest level document affected by change, propagating the change through the full set of documents. • At each step the process lets you redesign the system, based on analysis of the existing system.

7. The Interactive Enhancement Module(cont’d) • The process assumes that the organization is able to analyze the codes and make the necessary changes. • An environment that supports this approach also supports the quick fix module.

8. The Interactive Enhancement Module

9. The Full Reuse Module • Assumes a repository of documents and components defining earlier versions of the current system and similar systems. • The approach taken by this module is: • Start with the requirements for the new system, reusing as much of the old system as feasible. • Build a new system using documents and components from the old system. Develop new documents and components where necessary. • Packaging of the existing components is necessary and analysis is required.

10. The Full Reuse Module

11. Module Differences • The full reuse module frees you to design the new system’s solution from a set of similar solutions. • The interactive enhancement module takes the last version of the current system and modifies it. • The full reuse module offers a broader set of items for reuse. • The interactive enhancement module encourages tailoring the existing system to get the extensions for the new system.

12. Applying the Modules

13. Weaknesses

14. Bibliography • Basil R, Victor. Viewing Maintenance as Reuse Oriented Software Development. University of Maryland, 1990. • www.encarta.com