About the seminar

The first serious work on emulating the 1900 architecture started in 1999. The outcome was G3EE – George 3 Executive Emulator. David Holdsworth will speak on the origins of the project. Delwyn Holroyd will give an overview of how G3EE has subsequently proved useful in connection with the restored ICL 2966 at the National Museum of Computing.

One of the main aspects of the work undertaken by the 1900 group is the recovery and preservation of software. The majority of this arrives on magnetic tape. Delwyn Holroyd will discuss the techniques used to recover data from elderly tapes which are often not in the best condition.

Brian Spoor and Bill Gallagher will round off the afternoon with a discussion and demonstration of the emulation projects they have been working on. They will cover –

• A very brief introduction to the ICT/ICL 1900 series computers (for non-ICL aware attendees).
• Software recovery, notable finds and methodology.
• What we have recovered (and maybe what we would like to recover).
• Demonstrations of the software running under emulation.

About the speakers

Delwyn Holroyd started his career in computing in 1987 with ICL Mainframe Systems at West Gorton. During his time at ICL he worked with the Series 39 SX OCP, VME and Open TP teams. Since 1994 his work has been in the fields of non-linear video editing and visual effects compositing software. He is currently co-founder and Technical Director at Codex Digital, a company that provides recording and workflow solutions for the professional cinematography industry. Delwyn joined the National Museum of Computing in 2009 as a volunteer and leads the 2966 and HDC project teams.

Bill Gallagher started a career in computing after not completing a degree course at QUB in Maths & Applied Maths, mostly as a result of becoming interested in computing and computers. Worked for Wang in Dublin, then for 10 years of so for the Wang dealers in Belfast, where I specialised in writing custom device microcode for communications applications for the Wang VS systems. After leaving there in 1991, I worked for a software house specialising in VAX/VMS. That was, in retrospect a wrong move and I decided in mid 1992 to take the plunge and become self employed, at that time mostly in providing advice and installation services in the new and rapidly expanding field of networks – some Novell, but increasingly Windows NT. Throughout the time, I have always been interested in computing at many levels – the electronics, the logic, operating systems and languages. Having accreted a selection of machines, I started to want at least one instance of every computer that I ever used. Until David & Delwyn’s g3-exec there was a large, blue gap in that collection.

Brian Spoor entered the IT profession straight from school as a trainee programmer with the Liverpool Victoria Friendly Society in central London. Moved to the North East Thames Regional Computer Centre as a systems programmer with the responsibility of a bare metal installation (and then support) of the GEORGE 3 operating system at the new centre. Then to the GEORGE2+ development team at ICL Dataskil (a.k.a. Rent-a-Drunk) in Reading and moved to the computer graphics unit when G2+ development was being downsized. I then went on to work as an independent IT Consultant, designing, programming and installing custom software systems. Now retired, I spend my time reviving 1900 software and operating systems, while travelling between the UK and Italy. Still alive and in the UK (at the time of writing).

David Holdsworth writes –

I began my computing career as a physics research student writing Algol60 programs modelling quarks on a KDF9. After discovering that I might be better at computing than physics, I got a job at Leeds University in 1967 where we implemented the Eldon2 multi-access operating system on KDF9, which was still running at NPL in 1980. Leeds University’s KDF9 was succeeded by an ICL 1906A where I was involved with George3 and George4. At Leeds I was an early champion of Amdahl and of UNIX. In retirement my computational activity is on resurrection of historic software. Current focus is on KDF9 compilers. I believe that software is only really preserved if there is an environment within which it can be run. I believe that software is just as historic as hardware, but very little of it survives the passage of time. Yet it is so much easier to keep old software running than old hardware. Our profession has been negligent of its history.

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