SR (synchronizing resources) is a PASCAL - style language enhanced with
constructs for concurrent programming developed at the University of
Arizona in the late 1980s. MPD (presented in Gregory Andrews' book about
Foundations of Multithreaded, Parallel, and Distributed Programming) is
its successor, providing the same language primitives with a different
The run-time system (in theory, identical) provides the illusion of a
multiprocessor machine on a single 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,
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.
The integrated POSIX threads support of NetBSD-2.0 allows us to use
library primitives provided for NetBSD's phtread system to implement
the primitives needed by the SR run-time system, thus implementing 13
target CPUs at once and automatically making use of SMP on VAX, Alpha,
PowerPC, Sparc, 32-bit Intel and 64 bit AMD CPUs.
We'll present some methods used for the impementation and compare some
performance values to the traditional implementation.