A PMS Level Notation for the Description and Simulation of Digital Systems

Abstract

The description of structural aspects of a digital system presents certain requirements that are not covered by the semantics of ISPS or other behavioural description languages. To this end we have designed and implemented a specialised language based on the PMS level of design first introduced by Bell and Newell. The PMS notation described in this paper allows the specification of instances of components, their interconnections, and the validation of these interconnections. The notation blends easily with ISPS, and systems described in PMS can incorporate ISPS description of components whose structural aspects are to remain hidden or unspecified. To illustrate the use of both notations in the description of a complex system, we describe a computer consisting of a central processor, memory units, and peripheral units, connected through a DEC PEP-11 UNIBUS.