A Machine-Independent port of the MPD language run time system to NetBSD

MPD (presented in Gregory Andrews’ book about Foundations of Multithreaded, Parallel, and Distributed Programming[1]) is the successor of SR[2] (“synchronizing resources”), a PASCAL–style language enhanced with constructs for concurrent programming developed at the University of Arizona in the late 1980s[3]. MPD as implemented provides the same language primitives as SR with a different syntax which is closer to C. The run-time system (in theory, identical) of both languages provides the illusion of a multiprocessor machine on a single single– or multi–CPU Unix–like system or a (local area) network of Unix-like machines. Chair V of the Computer Science Department of the University of Bonn is operating a laboratory for a practical course in parallel programming consisting of computing nodes running NetBSD/arm, normally used via PVM, MPI, etc. We are considering to offer SR and MPD for this, too. As the original language distributions are only targeted at a few commercial Unix systems, some porting effort is needed, outlined in the SR porting guide[7] and also applicable to MPD. The integrated POSIX threads support of NetBSD-2.0 enables us to use library primitives provided for NetBSD’s pthread system to implement the primitives needed by the SR and MPD run-time systems, thus implementing 13 target CPUs with a onetime effort; once implemented, symmetric multiprocessing (SMP) would automatically be used on any multiprocessor machine with VAX, Alpha, PowerPC, Sparc, 32-bit Intel and 64 bit AMD CPUs. This paper describes mainly the MPD port. Porting SR was started earlier and partially described in [6] (Assembler and SVR4 cases) while only preliminary results for our new approach could be presented at the conference. Most of the differences between our changes to SR and to MPD could be done by mechanically replacing mpd by sr in the code; because of this, and because the