---
title: IBM PS/2 Model 25
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1987'
cpus:
- Intel 8086
params:
  name: PS/2 Model 25
  image: /media/museum/photos/ibm_model25_1s.jpg
  company: /companies/ibm
  company_name: IBM
  specs:
  - label: NAME
    value: PS/2 Model 25
  - label: MANUFACTURER
    value: IBM
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: august 1987
  - label: END OF PRODUCTION
    value: Unknown
  - label: KEYBOARD
    value: Full stroke keyboard, PS/2 type
  - label: CPU
    value: Intel 8086
  - label: SPEED
    value: 8 MHz
  - label: CO-PROCESSOR
    value: optional Intel 8087 (math co-processor)
  - label: RAM
    value: 512 KB, upgradable to 640 KB
  - label: VRAM
    value: Unknown
  - label: ROM
    value: Unknown
  - label: TEXT MODES
    value: Unknown
  - label: GRAPHIC MODES
    value: 'MCGA graphics : 640 x 480 in monochrome, 320 x 200 in 256 colours'
  - label: COLORS
    value: 262 144 colours palette
  - label: SOUND
    value: Internal PC buzzer
  - label: SIZE / WEIGHT
    value: Unknown
  - label: I/O PORTS
    value: Parallel port, 9pin serial port, 2 x ps/2 ports, 2 x internal expansion slots (8-bit)
  - label: BUILT IN MEDIA
    value: one or two 3.5'' floppy drives (720 KB each)
  - label: OS
    value: OS/2, DOS
  - label: POWER SUPPLY
    value: Built-in power supply
  - label: PRICE
    value: Unknown
  tabs:
  - photos
  forum_thread: 1151
  photos:
  - title: MODEL 25
    subtitle: ''
    text: ''
    image: /media/museum/photos/ibm_model25_1.jpg
  - title: REAR
    subtitle: ''
    text: Thanks to Brandon for this picture
    image: /media/museum/photos/ibm_ps2-m25_rear.jpg
  - title: MOTHER BOARD
    subtitle: ''
    text: Thanks to Brandon for this picture
    image: /media/museum/photos/ibm_ps2_m25_mobo.jpg
  - title: PS/2 RUNNING WINDOWS 3.0
    subtitle: ''
    text: |-
      Windows 3.0 running in high resolution with 16 shades of grey due to a VGA card installed.

      Thanks to Brandon for this picture
    image: /media/museum/photos/ibm_ps2_windows3_ss.jpg
  oc_id: 1183
  source:
    url: https://web.archive.org/web/20230608093550/http://www.old-computers.com/museum/computer.asp?c=1183
    date: '2023-06-08'
---

IBM was struggling in 1986 against Apple's Macintosh series, so IBM set out to create something that would defeat the Macintosh. IBM came up with a all-in-one similar to the Macintosh. However, the Model 25 & 30 were the low-end (budget) models of the PS/2 range.

The PS/2 Model 25 became quite popular with businesses, but never made it strong with the home market.

The PS/2 Model 25 & 30 were the only system using the MCGA (Multicolor Graphics Adapter) standard. They came with this video features built-in. MCGA offered all text and graphic modes of the CGA standard plus 640x480 monochrome and 320x200, 256 colors (out of a palette of 262,144). It announced the future VGA standard which will become much more popular.

Model 25 & 30 were also the only PS/2 systems using an 8-bit ISA bus (like PC ATs), as opposed to other PS/2 models which used a 16 or 32 bit MCA bus.

Thanks to **Alex Rushing** for info and picture

Further information from **Brandon**:\
The model 25 came in two models, a monochrome model, and a color model. The monochrome model usually is called "Type 001", the color one being "Type 004".. There never was a type 002, or 003.\
The motherboard for the color and black and white models are exactly the same, minus some revisions on the later years. They were always surface mounted though (most of the chips anyway).\
They are a tough machine, though when you install one in a new room, it NEEDS to let sit in the room for a couple hours, otherwise the power supply/motherboard will die.\
While the floppy drives were 720KB, they "could" use 1.44MB drives, as long as the interface was the same.\
They contain TWO BIOS's in them. One called the CBIOS, and the other called the ABIOS.. CBIOS is "Compatible BIOS", and is used for DOS or Windows 3.0 and under... ABIOS, or "Advanced BIOS", is used when it runs OS/2.. OS/2 is the native OS to this unit. They also had an option for a hard drive.

<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>