UNIX time-sharing system: A minicomputer satellite processor system

A software support system for a network of minicomputers and microcomputers is described. A powerful time-sharing system on a central computer controls the loading, running, debugging, and dumping of programs in the satellite processors. The fundamental concept involved in supporting these satellite processors is the extension of the central processor operating system to each satellite processor. Software interfaces permit a program in the satellite processor to behave as if it were running in the central processor. Thus, the satellite processor has access to the central processor's I/O devices and file system, yet has no resident operating system. The implementation of this system was considerably simplified by the fact that all processors, central and satellite, belong to the same family of computers (DEC PDP-11 series). We describe some examples of how the SPS is used in various projects at Bell Laboratories.