View Full Version : Gec 4000 Series Minicomputer Software/Listings/Info please !!

January 14th, 2015, 12:02 AM
Hello People,

After about 7 years owning a Gec 4070 Minicomputer, i'm still on the lookout for any more stuff on this British Mini Beastie.
I am particularly after program listings that can be entered via front Keys and also any in depth hardware information.
I really want to get this great bit of kit up and doing something interesting and possibly worth while ;).


January 14th, 2015, 01:43 AM
Whilst I worked on these "on and off" when I was at NERC


I am sorry to say I didn't keep any hardware or software from them. We mostly used them as X.25 switches. They are quite complex machines and I don't think there ever was any software that could be toggled in via the switches, but its been a long long time since I wrote any Assembler for these. I can't even remember the machines layout.

I see Darsebury still have some but I don't think they work:-


might be worth asking them. Jim Austin also has one, well a 4100:-



so he might have some software.

As these are archetypal British computers the BCS Computer Conservation Society or TNMOC @ Bletchly may be able to help. Try dropping Dik Leatherdale an e-mail. Hist contact details are here:-

http://www.computerconservationsociety.org/resurrection.htm#contact editor

or Kevin Murrell who is the CCS Secretary and also part of TNMOC, his contact details are at the bottom of this page:-


January 15th, 2015, 12:09 AM
Hello Dave,

Thanks for the info. I have looked at the sites before that you supplied links for (Cheers anyway) however I didn't know that Jim Austin has a GEC, he doesn't show it on his website as something that he owns, just lists. I am surprised that Daresbury still has a GEC, mine came from RAL which has links to there and mine was the last working unit from RAL (I saved it at the last minute before it was skipped, unfortunately all documentation was destroyed before I got there).
I thought of BCCS but as they do not seem to reference the GEC in any of their newsletters or restorations I assumed that there was probably no interest. I'll give Dik Leatherdale a try.
What are your memories of this old beastie (if any at all) ?


January 15th, 2015, 01:24 AM
I had a vague memory Jim Austin had a GEC but I have never seen any pictures of it.

There is one mention of GEC's in the CCS newsletters. There is probably "No Interest" as no one has given any one any GEC machines. I would hope that they would be interested and prepared to help given the role these machines had in Networking in the UK as part of both the original SERC/NERC network, and in the Post Office Prestel network.

I think TNMOC (and probably Jim) has a CAMTEC PAD so if you could find the X.25 software you could perhaps re-create an X25 network. If you could come with a proposal the CCS might even help with funding.

I only have dim memories of the machines, as my real role in NERC was Honeywell Systems Programmer and then IBM Systems Programmer. In NERC they were used as X.25 switch's and I still have a copy of the book Exeter used on the X.25 networking course that describes some of the hardware and software.

They were also deployed as end user computers at the British Geological Society at Edinburgh. It was almost Universally hated by the users as they were used to DEC Fortran on PDP-11 and VAX and of course GEC Fortran didn't have any of the extensions. It had a nasty (but standards compliant) "feature" where by if you did something like:-


it would do the division in single precision as "0.5" is a single precision constant. To get it to work you needed to write:-


which totally messed up the scientists.

I also modified a driver to try and get a Calcomp plotter working. I don't think it ever worked well....