website/content/museum/acorn-computer-archimedes-a4000.md

---
title: Acorn Computer Archimedes A4000
categories:
- Computers
types:
- Professional Computer
origins:
- United Kingdom
years:
- '1992'
cpus:
- ARM 250 32 bit RISC
params:
  name: Archimedes A4000
  company: /companies/acorn-computer
  company_name: Acorn Computer
  specs:
  - label: NAME
    value: Archimedes A4000
  - label: MANUFACTURER
    value: Acorn Computer
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: United Kingdom
  - label: YEAR
    value: september 1992
  - label: BUILT IN LANGUAGE
    value: BBC BASIC
  - label: KEYBOARD
    value: Full-stroke PC 102 keys style
  - label: CPU
    value: ARM 250 32 bit RISC
  - label: SPEED
    value: 12 MHz
  - label: CO-PROCESSOR
    value: MEMC (memory), VIDC (Video and Sound), IOC (I/O)
  - label: RAM
    value: 2 to 4 MB
  - label: ROM
    value: 2 MB
  - label: TEXT MODES
    value: Up to 132 columns x 32 rows
  - label: GRAPHIC MODES
    value: VGA video output. Several graphic modes. Among them 640 x 256 or 512 pixels
  - label: COLORS
    value: Palette of 4096 colours
  - label: SOUND
    value: 8 voices synthesizer
  - label: I/O PORTS
    value: Centronics, RS423, VGA, 1 expansion slot (same as A3000, A3010 and A3020)
  - label: BUILT IN MEDIA
    value: One 3.5'' FDD, 0 to 210 MB HDD
  - label: OS
    value: RISC OS 3.11
  - label: POWER SUPPLY
    value: Built-in power supply unit
  - label: PRICE
    value: Approx. £800
  tabs:
  - photos
  - hardware
  - emulators
  - links
  - docs
  photos:
  - title: LARGE VIEW
    subtitle: ''
    text: ''
    image: null
  - title: 'MAIN UNIT #1'
    subtitle: ''
    text: ''
    image: null
  - title: 'MAIN UNIT #2'
    subtitle: ''
    text: ''
    image: null
  - title: 'MAIN UNIT #3'
    subtitle: ''
    text: ''
    image: null
  - title: CASE
    subtitle: ''
    text: The A4000 case was a slim down version of the A5000's
    image: null
  - title: REAR PANEL
    subtitle: ''
    text: |-
      From left to right:

      • AC Power in/out sockets\
      • Keyboard mini din connector\
      • Parallel printer DB25 connector\
      • Serial RS232 DB9 connector\
      • Optional Econet DB15 connector\
      • Stereo sound output jack\
      • Standard DB15 video output\
      • The Midi card provides Midi Thru, Midi in, Midi out and User port connectors.
    image: null
  - title: OPENED
    subtitle: ''
    text: Note the clipped hard disk and floppy disk drive and the Midi expansion card.
    image: null
  - title: MOTHERBOARD
    subtitle: ''
    text: |-
      **(1)** ARM 250 CPU\
      **(2)** Expansion connectors\
      **(3)** RISC OS 3.11 ROMs\
      **(4)** Video and I/O custom chipset\
      **(5)** 4 MB RAM chips (2 MB standard + 2 MB in DIP ICs)\
      **(6)** FDD and HDD connectors.
    image: null
  hardware:
  - title: 486 CARD
    subtitle: ''
    text: Allowed Archimedes series computers to run 32-bit PC-DOS software. It was delivered with a manual, a driver disk and PC-DOS 6.3
    image: null
  - title: GRAPHICS ACCELERATOR
    subtitle: ''
    text: |-
      Graphics accelerator card (called "ColourCard") for A3000, Archimedes and A5000.\
      Company : Computer Concepts\
      Enhanced potential for Archimedes series including 15-bit desktop modes (i.e. 800\*600 @ 256 colours).

      Thanks to **Chris Syntichakis**
    image: null
  - title: CUMANA SCSI CARD
    subtitle: ''
    text: |-
      16-bit SCSI-1 card\
      Company: Cumana.\
      There are an external port for scanners/CD-ROM etc. and 2 internal ports for SCSI and Floptical drives.

      Thanks to **Chris Syntichakis**
    image: null
  - title: SERIAL CARD
    subtitle: ''
    text: |-
      From Atomwide's site:\
      High speed serial card featuring three ports, each in the shape of a standard 9-pin ‘D’ plug. Each port on the card is capable of running at up to 460,800 bits per second, and employs a 16-byte FIFO buffer to reduce loading on the host computer’s processor, so improving communications reliability. All serial cards are standard single-width podules, and are fully compatible with Atomwide 6 and 8-slot RiscPC backplanes.
    image: null
  - title: MIDI CARD
    subtitle: ''
    text: Allowed Archimedes systems to interact with any midi sound device.
    image: null
  emulators:
  - title: Arculator
    url: http://b-em.bbcmicro.com/arculator/
    platform: Windows
    text: An excellent Windows-based Archimedes emulator, plays many games and has simple usage.
  - title: Red Squirrel
    url: http://www.red-squirrel.org/
    platform: Windows
    text: An Emulator of Arm based Acorn machines for Windows 98/ME/2000/XP
  - title: Virtual Acorn
    url: http://www.virtualacorn.co.uk/
    platform: Windows
    text: Excellent but commercial software - £30
  - title: ARCHIE
    url: http://www.geocities.com/siliconvalley/campus/5427/
    platform: Multiplatform
    text: Archie is an emulation of the Acorn Archimedes hardware (A3xx/A4xx/A3xxx) for DOS/Windows
  links:
  - title: Web Wiz CAPTCHA
    url: http://www.webwizcaptcha.com
    text: ''
  docs:
  - title: TOM'S ARCHIMEDES DOCS (INTERNAL HARDWARE)
    url: http://b-em.bbcmicro.com/arculator/index.html
    cover: /media/museum/docs/couvs/vide.gif
    text: |-
      [**TOM'S ARCHIMEDES DOCS (INTERNAL HARDWARE)**](http://b-em.bbcmicro.com/arculator/index.html)written by Tom Mowalker

       compiled/archived by Tom Mowalker\
       type of document : HTML\
       source : [Arculator](http://b-em.bbcmicro.com/arculator/index.html)
  comments:
  - author: Chris (UK)
    date: Tuesday 1st February 2011
    text: |-
      Hi,\
      My old A4000 is sick, when it is booting there is a message "Internal error: undefined instruction at $03877AC8" does anyone have any clues about this ?? Is it corruption on hard drive or does this indicate hardware problems? or is the old machine on the way to the scrap yard?
  - author: Dean Graham (Selby, UK)
    date: Saturday 27th November 2010
    text: |-
      Hi Jamie,

      Thank you for your post! Im pleased to report I got the A4000 up and running and it now has an A3000 to keep it company.

      Cheers,

      Dean
  - author: Jamie
    date: Monday 22nd November 2010
    text: |-
      Dean:-

      You are probably not going to see this but yes it will work with a VGA monitor. PS2 Keyboard and mouse? I dont know
  - author: Bernadette (England)
    date: Friday 23rd May 2008
    text: |-
      My primary school had one of these, only one! I can't believe the difference ten to fifteen years makes, now my little sister goes to the same school and they have a computer suite with about twenty brand new PCs with broadband internet. (I am 25 and she is 8)\
      I remember my teacher showing me how to make pie charts on it, i think thats all we used it for!
  - author: Dean Graham (Selby, UK)
    date: Thursday 23rd February 2006
    text: |-
      Hi,

      I have an A4000 base unit only and would like to know if it will work ok with a standard PS2 keyboard, mouse and VGA monitor?

      Any help would be greatly apprecaited.

      Many thanks,

      Dean
  - author: George (hialeah)
    date: Sunday 15th May 2005
    text: woah, you are right.
  - author: Andy (England)
    date: Sunday 30th January 2005
    text: Hi, It looks like I'm the first to post here! ok, I'm posting cos theres a couple of details I'm sure aren't completely right here... as far as I remember, the A4000 had an 18Mhz CPU (though the RAM ran at 12Mhz), and 2Mb ROM, and the version I had had a 40Mb harddisc - I don't know if they did models without a hard disc, though I doubt it, as this was the 2nd highest spec of the systems they were producing at the time. Please correct me if I'm wrong!
  related:
  - /museum/acorn-computer-a4
  - /museum/acorn-computer-archimedes
  - /museum/acorn-computer-archimedes-a3000
  - /museum/acorn-computer-archimedes-a3010
  - /museum/acorn-computer-archimedes-a3020
  - /museum/acorn-computer-archimedes-a5000
  - /museum/acorn-computer-archimedes-a7000
  oc_id: 709
  source:
    url: https://web.archive.org/web/20230202014543/http://www.old-computers.com/museum/computer.asp?c=709
    date: '2023-02-02'
---

The Acorn A4000 was a slightly cheaper cut down [A5000](/museum/acorn-computer-archimedes-a5000/), with a shorter case, one expansion slot and an ARM250 processor.

Curiously, the machine had its floppy and hard drive fixed to the chassis with a wire clip which meant these could be quickly replaced without tools, whereas replacing the hard disk on the A5000 was a more fiddly operation requiring the expansion slot plane and the whole chassis holding the drives to be removed.

Many of the features (ARM250, VGA screen modes, RISC OS 3) of this model were implemented into the lower end A3010 and A3020 computers.

The keyboard was a much cheaper type more similar to a generic PC unit.

A rare 486 PC emulator on a card was available, similar cards became popular on the later RISC PC models.

Information supplied by **Jonathan Hayward**