(PCN) A specification language for parallelism between C and Fortran modules. PCN provides a simple language for specifying concurrent algorithms, interfaces to Fortran and C, a portable toolkit that allows applications to be developed on a workstation or small parallel computer and run unchanged on supercomputers and integrated debugging and performance analysis tools. PCN was developed at {Argonne National Laboratory} and the {California Institute of Technology}. It has been used to develop a wide variety of applications, in areas such as climate modelling, fluid dynamics, computational biology, chemistry, and circuit simulation. Version 2.0 runs on networks of workstations: Sun-4, NeXT, RS/6000, SGI; multicomputers: iPSC/860, {Touchstone DELTA}; and shared memory multiprocessors: Symmetry/Dynix. ftp://info.mcs.anl.gov/pub/pcn. E-mail: Ian Foster <pcn@mcs.anl.gov>, Steve Tuecke <tuecke@mcs.anl.gov>. ["Productive Parallel Programming: The PCN Approach", I. Foster et al, Sci Prog 1(1):51-66 (1992)]. (1993-02-12)

Program Composition Notation (PCN) is a specification notation for building up larger programs from smaller modules or programs (usually written in C or Fortran). Efficient parallel programming is at the heart of PCN.