A Main Program and Overlay Manager Subsystem Within a Distributed Function Laboratory Computer System

A key property of modern systems to control and acquire data from a collection of laboratory experiments is that the computer programs to effect this control and data acquisition are written in a high-level language, e.g., FORTRAN. The large amount of core memory required for execution of programs compiled from the FORTRAN language poses the most significant problem in the design of systems to support this language. A common method of solving this problem involves dividing the execution code into a main program and a set of associated overlays. A subsystem for developing and executing FORTRAN programs having such a main program-overlay structure can be implemented in many ways. The details of an implementation within a functionally distributed laboratory computer system are given. Emphasis is placed on the description of an auxiliary fast-access disk used as an intermediate storage device for read-only access information.