Hierarchical control programs for systems evaluation

The task of testing a complete operating and computing system has become increasingly difficult, primarily because of the growing complexity of today's systems. An operating system consists of a control program and a set of job programs; a computing system consists of at least one processing unit and various channels, control units, and input/output devices. Not only must each program and system device be individually tested to assure proper functioning, but the various interfaces between programs in the operating system and devices in the computing system must also be tested. Finally, all parts of the system must be pulled together for the complete systems test required to gauge the performance of the system and to check the functional relationship among operator, operating system, and computing system.