MUSS is the Manchester University Software System. It is an operating system that was designed and built at Manchester University for MU5, designed to be portable, and in fact ported to other machines.

In October 2017 I asked the editor of Resurrection, the Computer Conservation Society’s publication, to publish an appeal for information relating to MU5 to help my emulation project. Then, in December 2017 I received a response from Eur Ing. Brian Tompsett a lecturer at Hull University. He had a full set of printed MUSS documentation and a 9-track magnetic tape which he thought may have the same documentation on it. The interesting thing about MUSS documentation is that it is really a combination of documentation and code, written using a system called Flocoder. This meant that there may be machine-readable source code on the magnetic tape. However, Brian Tompsett thought that the tape may only contain the portable parts of the sources from the post MU5 era, covering MU6G, PDP11, VAX11 and MC68000. This also ties in with the printed documentation I have seen in a store room at Manchester, which all seems to be post MU5.

In April 2018 one of Brian Tompsett’s tapes was sent to The National Museum of Computing in Bletchley Park, where Delywn Holroyd read the tape successfully. It contained a tar file, inside which were a large number of documentation and source code files dated 13th April 1984.

The tape appears to contain the source code for Flocoder, the Manchester University system implementation language (MUSL) compiler, large parts of Version 11 of MUSS itself and other compilers, including Fortran and Cobol compilers that Brian Tompsett wrote. The source code is available here as free and open source software: MUSS Issue 11 Source Code, with qualified permission from Manchester University, as they are unsure as to whether any third parties have any rights over it. If anyone does have concerns about the publication of this code then please do let me know via the contact form on the home page.

MUSS Implementations

Within Manchester University MUSS was implemented first on MU5, but it was also implemented on MU6G, PDP11, VAX and MC68000.

MUSS was sold and used by ComputerVision and Honeywell and merged into their products. Brian Tompsett worked on MUSS and then worked for ComputerVision in 1981 onwards. All the ComputerVision products are now defunct.

Sperry-Univac also took an interest in MUSS. There is an MUSS User Manual for Issue 10 that was printed by Sperry Univac on 18 November 1982. It seems that Sperry provided some MC68000 machines to Prof. Derrick Morris’s group at UMIST.

It seems that MUSS was ported to one or more ICL 2900 computers. I have also been contacted by someone who ported to a Membrain in the 1970s.

MUSS Restoration

I am now working to get MUSS running once again. The work is being done on GitHub. You can find the project here.

The approach is first to hand build a processor to implement the Flocoder FLIP (Form LInear Program) program to extract the MUSL from the documentation, and then build a MUSL compiler that cross compiles to C. This will allow me to bootstrap the building of MUSS. It looks like it may be possible to get MUSS built for PDP-11 and VAX. I hope one day to be able to get it running on my MU5 Emulator as well.

I have now got a crude implementation of the Flocoder FLIP program written using Flex and Bison. It can take a Flocoder file from the MUSS sources and extract MUSL code. It is not yet possible to compile the extracted code as my FLIP implementation is still not entirely correct.

I also have the beginnings of a MUSL compiler. So far it can parse a slightly hand-modified version of one of the FLIP modules produced by my own implementation of FLIP. It does not do any code generation yet.

One Response to MUSS

  1. Pingback: MUSS Source Code Now Available | Rob's Old Computers

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