EINSTEIN: an internal driver in a time-sharing environment

EINSTEIN is an internal driver developed to evaluate the performance of a mixed-mode time sharing, batch operating system. It allows a single experimenter at a terminal to place an arbitrary, reproducible, interactive load on the system. Such a facility has numerous uses: system debugging and testing, benchmarking successive releases of a system, estimating system saturation points for different configurations, evaluating alternate processor and memory scheduling algorithms, etc. A task is defined either by specifying the values for a parameterized model of task behavior or by specifying the actual terminal input for the task, called the script. The parameterized model and the script-driven tasks are discussed in detail. An actual experience in which both types of EINSTEIN tasks were used to help isolate a reported performance degradation is related.