Syntax and Selmantics of PRETSEL-A Specification Language for Parallel Real-Time Systems*

For many real-time applications (e.g. Command, Control, and Communications), parallel computers of-fer a natural computing platform. However, very lit-tle attention has been paid to the specification require-ments of real-time systems implemented on parallel ma-chines. Towards this end, we propose a specijlcation language PRETSEL (Parallel REal-Time SpEcification Language). The PRETSEL specification language is based on a traditional two-level view of parallel comput-ing whereby a parallel computation is viewed as a col-lection of interacting (data) parallel algorithms. This view is naturally reflected in PRETSEL syntax where at the lower level various constructs are provided for the specification of a data-parallel real-time algorithm (data-parallelism). At the upper level another set of constructs is provided to combine such tasks in a variety of way (task-parallelism). Furthermore, the PRETSEL language allows for the specification of performance re-quirements. PRETSEL is currently being evaluated for real-time avionics applicaitons. In this paper we de-scribe the sysntax and operational semantics of PRET-SEL and establish results relating the functional and the temporal behaviors.