The World of 8086: 640k ought to be enough for everyone.

IBM Model 25 Details

IBM Model 25, Variant 8086

An entry-level IBM PS/2 system with ISA bus architecture and VGA graphics

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IBM PS/2 Model 25 IBM

About the IBM Model 25

A rare early IBM PS/2 variant featuring an Intel 8086 processor running at 4.7MHz. This compact desktop computer was part of IBM's Personal System/2 line, featuring VGA graphics and the traditional ISA bus architecture. The Model 25 was an entry-level PS/2 system, notable for its solid construction and reliable performance in business environments while maintaining compatibility with standard ISA expansion cards.

Intel 8086 processor at 4.7MHz
ISA bus architecture
Improved graphics capabilities

Interactive Experience Guide

Step-by-step pamphlet for hands-on demonstration

Experience History Firsthand

Want to interact with this legendary machine? Download our exclusive Experience Guide—a carefully crafted pamphlet that walks you through using the IBM PS/2 Model 25 just as users did in the late 1980s.

Boot sequence and system startup
PS/2 BIOS and configuration
Running classic software demonstrations
Historical context and insider tips
Download Experience Guide (PDF)

Key Features

PS/2 Architecture

Part of IBM's innovative Personal System/2 line with advanced system design.

Business Reliability

Solid construction and reliable performance designed for business environments.

Rare Variant

A rare early variant making it highly sought after by vintage computer collectors.

Historical Significance

The PS/2 Revolution

Introduced in April 1987 as part of IBM's Personal System/2 line, the Model 25 represented IBM's ambitious attempt to regain control of the PC market they had created. The PS/2 series introduced revolutionary technologies including VGA graphics, 3.5" floppy drives, and PS/2 keyboard/mouse ports. However, the Model 25 and Model 30 were entry-level systems that retained the traditional ISA bus, making them more affordable and compatible with existing expansion cards.

The Model 25 with its Intel 8086 processor occupies a unique place in computing history as an entry-level PS/2 system that bridged IBM's past and future. Unlike higher-end PS/2 models that featured the proprietary Micro Channel Architecture, the Model 25 used the familiar ISA bus, making it particularly significant for collectors and historians as it represents IBM's practical approach to market segmentation within the PS/2 line.

Technical Specifications

  • Intel 8086 processor at 4.7 MHz
  • 256KB RAM (expandable to 640KB)
  • 3.5" 720KB floppy drive
  • VGA graphics support (MCGA)
  • ISA bus (8-bit expansion slots)

PS/2 Innovations

  • Introduced PS/2 mouse and keyboard ports
  • VGA became the new graphics standard
  • 3.5" floppies replaced 5.25" drives
  • Improved system board integration
  • Better EMI shielding and reliability

Entry-Level PS/2 Strategy

The IBM Model 25 stands as a fascinating example of IBM's market segmentation strategy within the PS/2 line. While higher-end PS/2 models (50, 60, 70, 80) featured the revolutionary but proprietary Micro Channel Architecture, IBM wisely chose to keep the Model 25 and Model 30 with traditional ISA bus architecture to maintain affordability and compatibility with existing expansion cards.

This decision proved significant: while MCA ultimately failed to displace the ISA standard, many other PS/2 innovations became industry norms—VGA graphics, 3.5" floppy drives, and PS/2 keyboard/mouse ports remained standard for decades. The Model 25, with its 8086 processor and ISA bus, represents IBM's practical approach to bringing PS/2 innovations to budget-conscious buyers while avoiding the compatibility issues that plagued MCA-based systems.

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