Patent US 4,123,795

A stored program electronic digital computer has a control system for the computer. There are a plurality of processes in the computer. There are four stored program controllers in the computer which operate in different processors within the computer system. There is a master controller, a command controller, a task controller, and a disc I/O controller. These four controllers operate in a hierarchy of control. Each controller exercises control over a given level of work in the computing system.