Released in 1987, the IBM Personal System/2, or PS/2, marked IBM's second generation of personal computers, intended to replace its earlier models such as the IBM PC, XT, AT, and PC Convertible. This new line introduced a host of technological advancements that would significantly influence the broader IBM PC compatibles market. Many of these innovations, including the 16550 UART serial port, the 1440 KB 3.5-inch floppy disk format, 72-pin SIMMs,
the PS/2 mouse and keyboard port, and the Video Graphics Array (VGA), eventually became industry standards. Despite these forward-thinking features, the PS/2 faced considerable market challenges, particularly outside of its initial target corporate audience.
Pioneering New Standards
The PS/2 line was a crucible for several technologies that would define personal computing for years to come. The introduction of the 1440 KB 3.5-inch floppy disk format, for instance, helped standardize this smaller, higher-capacity disk across the industry, moving away from the larger 5.25-inch format. Similarly, the PS/2 mouse and keyboard ports, distinct six-pin mini-DIN connectors, became ubiquitous, replacing older, less standardized connections. The Video Graphics Array (VGA) was another major leap, effectively replacing the previous EGA standard. VGA increased graphics memory to 256 KB, offering resolutions of 640x480 with 16 colors and 320x200 with 256 colors, and provided a palette of 262,144 colors, a significant improvement over EGA's 64 colors. This analog RGB video output, using a 15-pin D-sub connector, became the de facto standard for monitors and projectors throughout the 1990s.
Beyond these widely adopted standards, the PS/2 also introduced the Micro Channel Architecture (MCA) on its higher-end models. MCA was a technically superior bus architecture, conceptually similar to the channel architecture of IBM's System/360 mainframes. It offered higher-speed communications, bus mastering, bus arbitration, and a primitive form of plug-and-play management. Features like streaming-data procedure, channel-check reporting, error logging, and internal bus-level video pass-through were advanced for their time, with transfer speeds comparable to the much later PCI standard. However, MCA's proprietary nature and IBM's licensing terms prevented its widespread adoption outside the PS/2 line.
Market Reception and Challenges
Initially, the PS/2 computers were popular among corporate buyers. By September 1988, IBM reported selling 3 million PS/2 machines within 18 months. However, the line struggled in the consumer market. IBM failed to effectively link the PS/2's Micro Channel architecture with the then-immature OS/2 1.x operating system in the minds of consumers, making it difficult to justify the PS/2's price premium compared to rival IBM PC compatibles that used industry-standard hardware and ran Microsoft Windows. Rival manufacturers also responded to MCA by forming the EISA bus standard, further fragmenting the market.
The proprietary nature of MCA created significant hurdles. Most major PC manufacturers were reluctant to accept IBM's licensing terms, particularly the per-machine royalties. Setting up MCA cards also proved user-hostile, requiring a special setup disk for each machine and card. This meant users had to keep a specific floppy disk matched to each PC, a logistical nightmare for large organizations. Without the correct, updated floppy disk, no changes could be made to the PC's cards. This complexity, combined with the high cost and a lack of third-party 32-bit expansion cards, contributed to the Model 80's mediocre sales, which consistently trailed behind competitors like Compaq's Deskpro 386 line. By 1992, Macworld observed that IBM had "lost control of its own market and became a minor player with its own technology." The PS/2 line was officially retired in July 1995, marking the end of an era for a series that, despite its innovations, ultimately struggled to maintain market dominance.
