---
title: ICL Quattro
categories:
- Computers
types:
- Professional Computer
origins:
- United Kingdom
years:
- '1985'
cpus:
- 8086-2
params:
  name: Quattro
  image: /media/museum/photos/icl_quattro_system_1.jpg
  company: /companies/icl
  company_name: ICL
  specs:
  - label: NAME
    value: Quattro
  - label: MANUFACTURER
    value: ICL
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: United Kingdom
  - label: YEAR
    value: '1985'
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: Full stroke 102 key with function and arrow keys and numeric keypad
  - label: CPU
    value: 8086-2
  - label: SPEED
    value: 8 MHz
  - label: CO-PROCESSOR
    value: Socket for 8087 math coprocessor
  - label: RAM
    value: From 128 KB to 1 MB
  - label: ROM
    value: 40 KB
  - label: TEXT MODES
    value: 80 chars x 25 lines
  - label: GRAPHIC MODES
    value: 640 x 400 dots (ICL terminals)
  - label: COLORS
    value: Monochrome or 8 colours
  - label: SOUND
    value: Beeper
  - label: SIZE / WEIGHT
    value: Unknown
  - label: I/O PORTS
    value: 6 x serial RS232 ports, custom serial port, RS422 port, RGB port
  - label: BUILT IN MEDIA
    value: 1 or 2 x 5.25'' 800 KB floppy drives, 10 or 20 MB hard disk
  - label: OS
    value: Concurrent CP/M V.3.1
  - label: POWER SUPPLY
    value: Built in switching power supply unit
  - label: PERIPHERALS
    value: RAM expansion, 2nd 20 MB hard disk, ICL monitors and printers
  - label: PRICE
    value: |-
      Model 19: £2195 - Model 39: £4395 - Model 49: £4995\
      Monochrome terminal: £899 - Colour: £1399
  tabs:
  - photos
  forum_thread: 833
  photos:
  - title: INSIDE
    subtitle: ''
    text: |-
      **(1)** 2 cards was used for hard disk control. In fact, it was original old 'Black Box' cards\
      **(2)** CPU and ROM card\
      **(3)** 3 x 256 KB RAM cards\
      **(4)** Serial and I/O card\
      **(5)** 6 x serial RS232 ports\
      **(6)** Custom serial port\
      **(7)** RGB port. Was not used for a colour monitor, but for the connection of a video system to create slides, or a projector to show them\
      **(8)** Custom synchronous port. Gives the link to ICL or IBM mainframes\
      **(9)** Switching power supply unit\
      **(10)** 800 KB 5.25" floppy drive\
      **(11)** Rodime 20 MB hard disk drive
    image: /media/museum/photos/icl_quattro_inside_1.jpg
  - title: ICL TERMINAL KEYBOARD
    subtitle: ''
    text: ''
    image: /media/museum/photos/icl_quattro_keyboard_1.jpg
  oc_id: 852
  source:
    url: https://web.archive.org/web/20221209194127/http://www.old-computers.com/museum/computer.asp?c=852
    date: '2022-12-09'
---

With the Quattro, ICL attempted to tackle the multi-user market which was still opened with neither definitive system nor operating system.

The Quattro was a development of earlier ICL [Personal Computer](/museum/icl-personal-computer/) which in turn was a development of the [Rair Black Box](/museum/rair-microcomputer-black-box/)

The machine was named Quattro as it supported up to four users, each user running up to four programs simultaneously.

Internal hardware design was quite similar as the Personal Computer's. An eight connector backplane supporting logic boards. However, the CPU board featured a 16 bit 8086-2 and up to 1 MB of RAM could be installed.

Thre models were available:\
**Model 19** with 256 KB RAM and 2 x 5" 800 KB floppy drive,\
**Model 39** with 512 KB of RAM, one floppy drive and one 10 MB hard disk,\
**Model 49** same as Model 39 but with a 20 MB hard disk.

The Quattro could work with wirtually any video terminal. ICL supplied its own monochrome (6402G) and colour (6404G) graphic versions along with a 102 key keyboard.

It was delivered with Concurrent CP/M Operating System, later called Concurrent DOS, a true multi-tasking, multi-user O.S. which offered a very limited compatibility with MS-DOS.\
Sadly, few major software of the time, running on the first IBM PC and clones, were adapted to the specific features of the ICL. This is the main reason why the Quattro didn't meet any success, except near some corporate customers who already used ICL mainframes.

<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>