Files
yann64andClaude Opus 5.5 b274874139 All machines linked to their forum thread (full comment import)
1,289 discussions, 9,527 archived comments; pages no longer carry the comments themselves.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YDRjtmAiNpo5mK5N3d7QwZ
2026-10-13 17:26:43 +02:00

95 lines
3.9 KiB
Markdown

---
title: Merlin M4000
categories:
- Computers
types:
- Professional Computer
origins:
- United Kingdom
cpus:
- Intel 8086
params:
name: M4000
image: /media/museum/photos/bt_merlin_m4000_1s.jpg
company: /companies/merlin
company_name: Merlin
specs:
- label: NAME
value: M4000
- label: MANUFACTURER
value: Merlin
- label: TYPE
value: Professional Computer
- label: ORIGIN
value: United Kingdom
- label: YEAR
value: 198x
- label: BUILT IN LANGUAGE
value: None
- label: KEYBOARD
value: 114 keys full stroke with numeric keypad
- label: CPU
value: Intel 8086
- label: SPEED
value: Unknown
- label: RAM
value: Unknown
- label: VRAM
value: Unknown
- label: ROM
value: Unknown
- label: TEXT MODES
value: Unknown
- label: GRAPHIC MODES
value: Unknown
- label: COLORS
value: Amber monochrome
- label: SOUND
value: Unknown
- label: SIZE / WEIGHT
value: About 12kg
- label: I/O PORTS
value: Unknown
- label: BUILT IN MEDIA
value: 2 x 5.25 inch or 3.5 inch (720 KB) floppy drives
- label: OS
value: Concurrent CP/M-86, Concurrent DOS?
- label: POWER SUPPLY
value: Power supply built-in
- label: PERIPHERALS
value: Unknown
- label: PRICE
value: Unknown
tabs:
- photos
forum_thread: 1225
photos:
- title: M4000
subtitle: ''
text: Thanks to Riaz Sobrany for this picture
image: /media/museum/photos/bt_merlin_m4000_1.jpg
oc_id: 1258
source:
url: https://web.archive.org/web/20230318004515/http://www.old-computers.com/museum/computer.asp?c=1258
date: '2023-03-18'
---
The BT Merlin M4000 is a very obscure computer from the mid 1980s. It is allegedly based on the Logica Kennett, and should not be confused with the [BT Merlin Tonto](/museum/merlin-tonto/) which is a rebadged [ICL OPD](/museum/icl-opd-one-per-desk/).
The exact application of M4000 is unknown, but it was almost certainly developed for internal use by BT and never sold on the open market. It could have been used in conjunction with System X telephone exchanges.
---
**Contributors**: Riaz Sobrany
**Stevie Skellett** (UK) reports:\
These machines were certainly used outside of BT. The Royal Navy used them for admin tasks in the 80's. The machine I used had a 3.5" 720K floppy drive and a 20MB 'Winchester' hard disk. The OS was Concurrent DOS if I remember right. You could have 4 virtual terminals selected from a keyboard key. We had a vastly underrated, if not very user friendly, WP package called Lex9b. Once you learnt all its tricks, many of which did not figure in our user documentation, you could really make it sing. Mine also had another, similar sized, unit containing the Tape Backup Drive - backups took a \*long\* time!
**Ray Chester** adds:\
The DSS used these computers. Installed and maintained by BT Merlin. The systems were built for specific functions for example "Social Fund" had a couple of units with Social fund software and a Dot matricx printer. These machines would keel over from any passing static charge. They also had the Asteroids game written for them lol
**Col** comments:\
My introduction to IT. I worked on these for 5 years or so. These were used extensively outside BT. Major government contracts (as above post mentions), used by the armed forces and small companies such as solicitors etc. Also used by most of the theatres in the UK, using a box office app called RITA. They ran bespoke software apps and also had a word processor app called "Merlinword". Other variants had single floppy and 10 or 20meg hard drive. Also an 80meg hard drive or a Tandberg tape drive in its own casing. The RITA system even networked these together, using ARCNET. The nodes were addressed by using jumpers on a network daughter board. Oh happy days !
<table> <tr> <td></td> <td>We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.</td> <td></td> </tr> </table>