Software Maintenance and the 3R's - Reverse Engineering, Reengineering and Reuse

ion is an upward movement and is usually called Reverse Engineering. The Institute of Electrical and Electronics Engineers standard [IEEE 1993] defines it as: the process of extracting software system information (including documentation) from source code. Typically, it means going from source code to specifications. It does not change the system, but allows one to view the system at different levels of abstractions. • Alternation: Alternation is the process of manipulating information about a system’s characteristics by making one or more changes to a system representation without changing the degree of abstraction. It includes the addition, deletion and modification of existing information. It provides a bridge between abstraction and refinement. Reengineering is the process that starts with the existing system and produces a target system. Figure 5 illustrates this process and further illustrates that there can be sev-