Click Here to visit our Sponsor
The Latest News ! The History of Computing The Magazine Have Fun there ! Buy books and goodies
  Click here to loginLogin Click here to send a link to this page to a friendTell a FriendTell us what you think about this pageRate this PageMistake ? You have mr info ? Click here !Add Info     Search     Click here use the advanced search engine
Browse console museumBrowse pong museum


C64 maze generator T-shirts!

see details
Ready prompt T-shirts!

see details
Spiral program T-shirts!

see details
BASIC code T-shirts!

see details
Pixel Deer T-shirts!

see details
Shooting gallery T-shirts!

see details
Pak Pak Monster T-shirts!

see details
Vector ship T-shirts!

see details
Breakout T-shirts!

see details
Pixel adventure T-shirts!

see details

M > MERLIN > M4000


This mini forum is intended to provide a simple means of discussion about the Merlin M4000 computer. If you want to share your own experience or memories, or add relevant information about this system: post a message! For other purposes like sales messages, hardware & software questions or information requests, please use our main forum.

  Click Here to add a message in the forum


Thursday 2nd October 2014
John Desmond (Surrey/UK)

The M4000 range was used across several major contracts. These included OASIS for the Royal Navy, RITA - ticketing for theatres, DSS case paper location with Siemens and Wenger printers. Plus some specials such as the post room in the basement of Buckingham Palace and in the Houses of Parliament. I used to work for BT Business Systems, Walpole House in Ealing and covered the country as a field engineer. The M4000 had additional memory cards located below the main motherboard, an Arcnet network card and additional support for two more screens and keyboards via another adapter card. The M4000 was effectively the Logica Kennet and the Kennet versions were used in GP Surgeries and NHS sites by a third party company called Vamp Health, now known as In Practice Systems Ltd. As stated elsewhere, The Forestry Commission used quite a few of these around its UK sites. They were also sold to other government departments with MerlinWord and Ricoh 1600 daisywheel printers for word processing in big typing pools.

Tuesday 7th February 2012
Andy Dingley (South Wales)

I worked for BT AT (Applied Technology - an early consultancy and external systems developer, in the now common style) in Newcastle from ''85 to ''87, mostly on a large project for the D(H)SS. We only had a handful of PCs and rather more of the M4000s running CPM/86. We regarded these as far better than the IBMs! The amber monitors were clearer than IBM''s blurry greens and the build quality of the hardware was rock-solid (Logica did know how to build a good boat anchor). Best of all though was the multiprocessing capability of CPM/86 and the four virtual screens with rapid hot-key switching between them.

Software was much the same as MS/DOS, at least where things had been ported. Most of my work was Pascal programming, using Prospero Pascal (that I''d used since Z80 CP/M) and Wordstar as an editor.

The biggest project I did with the M4000 was part of the broader DHSS project. This was a terminal concentrator / forms interpreter running on ITL minis (a dinosaur even then). To test this and emulate an office full of busy typists we (well, I and Dr Russell Mulcahy) built a network of 20 M4000s, networked with ArcNET. Each M4000 had smart serial cards (on-board processor) installed so that it could run 4 serial connections simultaneously. A typist-emulator script could be run across 80 instances at once, using CPM/86''s multi-tasking so that the script interpreter only needed to be a simple single-thread program. The whole system was so successful for testing that the DHSS bought a complete duplicate for their own tests.

Friday 25th July 2008
Charles Durrant (UK)

BT Merlin M4000 (Logiva VTS-2400 "Kennet")

I worked for Logica VTS in Swindon between 1984 and 1986 (when VTS was closed) in the software development division. At the time I joined the main product was the VTS-2200 (internally called "Whirlwind") dedicated Word Processing system, based on the Intel 8086 running custom software (Firmware, OS and WP application) and with 1 or 2 40 track 5.25" floppy disks and monochrome text only displays. These were also re-badged by ICL (as the DRS-8801), British Telecom (as the M3300) and Nexos. They could be networked on a Cambridge Ring and were also used internally as development workstations running an Intel development system (8086 assembler and PL/M-86).

The next generation machine developed by VTS was the VTS-2400 or "Kennet". The Kennet was also based on the Intel 8086, but was designed as a more general purpose office computer in the style of an IBM PC system unit. It could have various combinations of storage devices, 1 or 2 80 track 5.25" floppy disks, 1 or 2 internal 10Mb Rodime Winchesters, an external 76Mb Fujitsu Winchester and/or an external 150Mb Tandberg QIC tape unit. They were reasonably modular, able to take additional cards for networking (Cambridge Ring or ArcNet, IBM Sync. Comms cards), additional memory, multi-port serial cards etc. It also had bitmapped graphics (initially monochrome, and later, a colour prototype).

In addition to the Word Processing software, MS-DOS and CCP/M-86 (later Concurrent DOS) were ported to the machine, allowing general office applications to run on the system, and I seem to remember a project that ported GEM (Digital Research's graphical windowed system - an early competitor to Microsoft Windows).

However, the Kennet was NOT IBM PC compatible, and so could not run the major business applications around at the time as these were tied to the IBM PC hardware. There were limited sales into specific projects, and the product was badged by BT (as the Merlin M4000). After VTS closed, British Telecom funded an independent team of software developers (Cognosys Limited) to port the Wordprocessing Software to their next generation of IBM PC compatible machines (based on Zenith hardware). This was to be called "Merlinword 5000", but I'm not at all sure it ever saw the light of day as a commercial product. Cognosys also developed a module for a document exchange system called CrossPak to allow migration of documents in the VTS WP system format to other PC compatible systems.

Ray Chester and Chris Timson are correct in mentioning the DSS use of Kennets. I was the consultant who worked with the DSS development team in Reading for 3 months (having been in the Logica VTS team that ported MS-DOS and CDOS to the Kennet). And am slightly embarrassed to admit that I also wrote the "Asteroids" game mentioned (initially as a demonstration of the Kennet's bitmapped graphics). Users of the VTS Wordprocessing system may also recall another (text based) game called "Space", which was popular among the Logica developers (and probably also escaped into the wild).

Thursday 11th October 2007
Bill Perry (UK)

I worked on these out of an MEC (Merlin Engineering Centre) in Avonmouth Bristol. As stated they were based on the Logica Kennet and followed on from BT Merlin purchasing (via ICL) an earlier Logica computer sold as the M3300 which was just a word processor.

M4000s were sold as a part of large contracts. e.g. As stated before they were sold into the Navy as part of the OASIS II project, a stores application used on shore (HMS Raleigh had some for training) and ships. It was interesting seeing on ships where these got installed, into VERY tight spaces;

To the DSS for 3 jobs, (i) casepaper location as Chris says, with a Siemens bubble jet printer, (ii) as a system to calculate benefits with a large and heavy MannismanTally double head dot matrix printer and I can't remember the 3rd! They were installed all across the country in all DSS offices and I think were the first computers to enter these offices in general use. We had a problem with interference on the HDs and we had to have a retrofit program to fit aluminium shields to the drives perhaps to stop the problems mentioned before about static. I remember as I organised the teams across the country to do this;

As the theatre booking system as stated. It was installed into the Bath Theatre Royal (I helped install and maintain it). The RITA software was written either by or in conjunction with the Royal Shakespeare Company. The software was advanced for its time;

And the Forestry Commission had some in their offices across the country too.

John's right in his description of the insides. I had a tool until recently that was used to pull out the memory boards. An extending yellow hook, as the boards slid on runners under the mother board, the first plugged into a daughter board behind the front of the case and then into each other towards the back.

The asteroids game was very good as a means of testing the system ;-)

Merlinword was based on the program that came in the M3300. It was an advance on Wordstar that was around at the time as it showed on screen underlining and characters as enboldened. In Wordstar you just had the ^S or ^U characters either side of the words showing these features.

John, I never saw these running MSDOS or Wordstar or Lotus, are you sure that wasn't on the M5000 range?

The colour of the case in your picture, was the colour of the Kennet case and looks like an early model where the badges were changed.

I'm unaware that it was ever used in System X exchanges, though in BT anything was possible!

It was sold into some BT offices, BT HQ had some but it was mainly produced for external sales.

It was replaced by the M5000 range of rebadged Zenith PC computers running MS/DOS.

Saturday 18th August 2007
Chris Timson (UK)

My introduction to IT as well. I escaped from the DSS local office front line, was taught Cobol and worked on the software that went back into the local offices. Casepaper Location was my particular baby, tracking files as they moved from one room to another. The M4000 was at the heart of an extraordinary RS232 based network of HP handhelds with barcode readers. Amazing it ever worked but it did, and quite well too.

The photo makes it look grey, but in fact it was a sort of neat beige colour.

Oh, that Asteroids game was written by the guy who led the XIOS (DR jargon for Bios) team at Logica. We had him for some consultancy and he gave us a copy of the game, and we in turn made sure it got out to the local offices.

Friday 25th May 2007
John (UK)

The M4000 was indeed a rebadged Logica VTS Kennet. It could run either the dedicated MerlinWord word processor program, MSDOS, CP/M-86 or Concurrent DOS (CDOS). It wasn't IBM PC compatible, but applications such as Wordstar or Lotus-123 were available. The screen was usually amber monochrome, but some colour screens were sold. The 'top-end' system would be a CDOS machine with one floppy (800k) plus a hard disk (10MB) plus the GEM graphics environment, and an Arcnet LAN card. This allowed DR-Net to be run to allow files or printers to be shared. I think the maximum RAM was 768KB, made up of 256KB on board plus two additional 256KB RAM cards. I have a brochure somewhere, I'll add some more details once I find it. The M4000 once appeared on Brookside (Channel 4 TV soap), it was also sold to places like the Stratford Theatre to run their booking system. It also had a neat telephone directory / database program which was used by a few switchboard operators.

Click here to go to the top of the page   
Contact us | members | about | donate old-systems | FAQ
OLD-COMPUTERS.COM is hosted by - NYI (New York Internet) -