A structure for interprocess communication in a data communications handler

Abstract

The use of an implementation which models a simple single server queuing system to control transfers between processes in a communications handler is described. Exchanges between processes are carried by three word elements, called LINKs, which are used to transfer control information and to assign data to processes. The managements of interactions by the single queue structure is used to coordinate parallel, time-independent operation of the attached processes, with the interface provided by the LINKs giving a simple yet flexible interface between activities. The implementation is a special purpose operating system designed for use in a PDP-11 computer dedicated to handling transfers of control and data between a number of communicating processes, which are connected to the PDP-11 by communications lines, direct memory access interfaces and shared memory.