Lurking within COBOL PERFORMs

Abstract

COBOL-implemented systems commonly rely on the PERFORM verb to provide structure and iteration in the software. Because of that key role, shortfalls in the use of PERFORM can lead to challenging difficulties in both enhancive and corrective maintenance. This paper explains the source of many of the symptoms by examining the way the compiler-generated object code executes. Then it classifies the symptoms by their pattern and relates the classes to the normally hidden generated code. In closing, the paper offers six positive actions to improve COBOL software using the PERFORM verb, and points to their contribution in enhancive and corrective maintenance, software quality assurance, systems improvement, and the management of software maintenance.