Monitoring dynamic properties of data processing system - using autonomous observation computer with direct memory access management

摘要

A monitoring system measuring the dynamic properties of a data processing system contains an autonomous observation computer with direct access to the data processing system central memory. The monitoring system observes the internal data processing system state only when settled. The consistency of the data processing system state is not disturbed by the program running in the monitoring system while it has access. An address comparator detects the end of each program or subprogram in the processing system which changes the observed data. The detection of the end of such a program is followed by the beginning of access by the observing computer. This is managed by a circuit which controls a memory coupling unit connected to the data processing system address and data bus. The management circuit is reset at the end of each access.