A primary requirement is that the systems software functions with the other elements of the software, the hardware and the applications so that errors are not introduced. This software contains many functions which, if used improperly, could cause substantial damage to data and software. In writing this paper we have assumed that the hardware in use in any organisation is configured to meet the business requirements. This gives rise to a multiplicity of structures which render the traditional descriptions of mainframe, minicomputer and PC open to misunderstanding by readers. We have therefore not sought to describe the components in detail.
Physical hardware is basically reliable and breaks down infrequently.
Failures in communication systems are more frequent particularly over long distances. If through malfunctioning the hardware causes an integrity failure in the stored data then it is our contention that this should be capable of detection through the application software. It is important however that failures of hardware are detected promptly and recovery effected as soon as possible after the event. It is this data which both governs the specific operation of systems and records the events of an organisation. Data provided to systems will have specific integrity attributes at the time of input, or generation.