This paper appeared in First International Conference of the Austrian Center for Paral
lel Computation Salzburg Austria pages Springer Verlag Lecture Notes in
Computer Science
Mo dula and its Compilation
Michael Philippsen and Walter F Tichy
Universit at Karlsruhe
email philippsen ira uka de
start with the problem sp eci cation and not with a se
Abstract
quential implementation In a sequential program to o
many opp ortunities for parallelism have b een hidden
Mo dula an extension of Mo dula is a program
or eliminated
ming language for writing highly parallel programs in
The second approach is to write programs that
amachine indep endent problem oriented way The
are explicitly parallel We claim that only minor ex
novel attributes of Mo dula are that programs are
tensions of existing programming languages are re
indep endent of the numb er of pro cessors indep endent
quired to express highly parallel programs Thus pro
of whether memory is shared or distributed and inde
grammers will need only mo derate additional training
p endent of the control mo des SIMD or MIMD of a
mainly in the area of parallel algorithms and their
parallel machine
analysis This area fortunately iswell develop ed
This article brie y describ es Mo dula and dis
see for instance textb o oks and In compiler
cusses its ma jor advantages over the data parallel pro
technology however new techniques must b e found
gramming mo del We also present the principles of
to map machine indep endent programs to existing ar
translating Mo dula programs to MIMD and SIMD
chitectures while at the same time parallel machine
machines and discuss the lessons learned from our rst
architecture must evolve to e ciently supp ort the fea
compiler targeting the Connection Machine Wecon
tures that are required for problem oriented program
clude with imp ortant architectural principles required
ming styles
of parallel computers to allow for e cient compiled
We take the approach of expressing parallelism ex
programs
plicitly but in a machine indep endentway In sec
tion we analyze the problems that plague most par