hide random home screenshot http://www.llnl.gov/sisal/SisalHomePage.html (World Wide Web Directory, 06/1995)

Sisal - A High Performance, Portable, Parallel Programming Language

Mission The objectives of the Sisal Language Project are to develop high-performance functional compilers and runtime systems to simplify the process of writing scientific programs on parallel supercomputers and to help programmers develop functional scientific applications.

Impact Functional languages such as Sisal provide a low-cost approach to developing parallel computing applications that still offer high performance and portability. This is of major significance, as parallel software costs are projected to top $1 trillion. Despite the commercial availability of multiprocessor computer systems, the number of parallel scientific and commercial applications in production use today remains small. It is estimated that the worldwide cost of developing software for sequential machines will reach $450 billion in 1995. Even if only a quarter of the software is parallelized, it would cost at least an additional $550 billion. Functional programming can reduce this increased cost while still providing high performance and portability.

Parallel Programming

Parallel programming in imperative languages, such as Fortran and C, has proven difficult. These languages, developed for sequential computer systems, do not naturally support parallelism. In addition to expressing the algorithm, the programmer must encode the program's synchronization and communication operations and safeguard against race conditions. The extra programming complexity increases costs, and the time-dependent errors that can occur in these languages can frustrate even the most experienced programmers. Click here for more info on Sisal's parallel language technology.

Functional languages, such as Sisal, promote the construction of correct parallel programs by isolating the programmer from the complexities of parallel processing. Based on the principles of mathematics, Sisal exposes implicit parallelism through data independence and guarantees determinate results. Click here for more info on Sisal's mathematical foundations.

Functional programming by itself does not address the problem of existing code. Sisal can offer significant advantage in porting existing programs to parallel computers by way of its Foreign Language Interface. Click here for more info on Sisal's advanced capabilities.

Performance

Today, most Sisal programs outperform equivalent Fortran programs compiled using automatic vectorizing and parallelizing software, and run comparably to hand-written parallel Fortran codes. Due to the simplicity of the functional programming model, the development cost of Sisal programs is less than that of Fortran programs by factors of up to seven. Click here for more info on Sisal's system software and the computers Sisal runs on. Click here to enter a set of pages containing Sisal's performance data on various programs run on various computers.

Spreading the Word

We are currently involved in numerous partnerships, formal and informal, and wide-ranging in scope, to provide Sisal to the commercial sector, as well as to other R & D organizations, world wide. Click here to learn more about the Computing Research Group's technology transfer partnerships.

We maintain a number of mailing lists for interested parties and Sisal developers:

The Computing Research Group is part of the Institute for Scientific Computing Research at LLNL. The ISCR is a UC institute that suports collaboration between scientists at the UC campuses and those at LLNL by conducting projects that advance and strengthen the ties between scientific computing and computer science. For more information on ISCR, access the ISCR WWW server.

The Sisal Language Project has been approved as a Designated Unclassified Subject Area (DUSA) K19222, as of 07 August, 1991.

To access the Sisal compiler, debugger, system support software, example program code, and documentation files, connect to the Sisal FTP Server.

To see descriptions of the anonymous ftp server contents, access the Sisal FTP Server README file .

If you have questions about this page or the Sisal Language Project, contact
John Feo -- feo@diego.llnl.gov or (510) 422-6389
or
Tom DeBoni -- deboni@llnl.gov or (510) 423-3793

LLNL Disclaimer
UCRL-MI-117383