A Method for Monitoring Occam Internal Channel

In a Transputer environment, where the data exchange and the synchronizations between any two processes are carried out by means of I/O operations, the monitoring of the channels used for implementing the message exchange is of particular interest. In this paper a method is illustrated for monitoring the internal channels of an Occam program. This method introduces little CPU overhead, no additional communication cost, and preserves the synchronization behaviour of the two communicating processes. Its characteristics have been attained by means of a particular monitoring mechanism, based upon a rather unusual use of some Transputer machine language instructions, canonically used to implement guarded communications within the Occam ALT construct.