ALGOL 68RS

ALGOL 68RS is the second ALGOL 68 compiler written by I.F. Currie and J.D. Morrison at the Royal Signals and Radar Establishment. Unlike the earlier ALGOL 68R it was designed as a portable compiler and implemented the language of the revised Report.

Versions of ALGOL 68RS were written for the ICL 2900 Series, Multics and VAX/VMS.

Subsequently portions of this compiler were put into the public domain - as an ALGOL 68 to C translator - as part of the public release of ELLA.

Although the ALGOL 68R compiler written by I.F. Currie, J.D. Morrison and S.G. Bond was a great success it suffered from two major problems—it had been written for the nearly obsolete ICL 1900 computer and it implemented an out-of-date version of the language as it was released before the Revised Report on ALGOL 68 was available.

RSRE needed a newer compiler for various internal projects so the team of Currie and Morrison wrote a new compiler designed for machine independence. The compiler itself dealt with the parsing of ALGOL 68, producing a high level intermediate language known as stream language that would then be compiled to machine code by a translator. The compiler only needed to know the sizes of the various object machine types and the character set available.

The compiler was written in ALGOL 68, bootstrapped initially using the ALGOL 68R compiler.

A team of two programmers at Oxford University Computing Services wrote a code generator for the ICL 2900 series.Martyn Thomas of SWURCC arranged that this system be sponsored by ICL and sold as an official ICL product.

Later the Avon Universities Joint Computer Centre, a large user of MULTICS requested the SWURCC team to produce a MULTICS version of ALGOL 68RS. A version for the DEC VAX computer was also written.

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