IBM PS/1

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The IBM PS/1 personal computer was IBM's return to the home market in 1990, five years after the IBM PCjr.

1 Position in IBM's PC Brands
2 "DOS in ROM" Models
3 Post "DOS in ROM" Models
4 Discontinuance
5 See also
6 References

[edit] Position in IBM's PC Brands

Like the PCjr, the PS/1's name suggested a more limited machine than IBM's business line, the PS/2. However, the PS/1 had a higher degree of compatibility with IBM's business computers. The PS/1 line was sold in consumer electronics stores alongside comparable offerings from Compaq, Hewlett-Packard, Packard Bell, and others.

[edit] "DOS in ROM" Models

IBM PS/1 (model 2011)


Type	Personal computer
Released	(unknown)
Discontinued	(unknown)
Processor	Intel 80286 @ 10 MHz
Memory	1 MB ~ 2 MB
OS	PC-DOS 4.01 (in ROM)

The original PS/1, based on a 10 MHz Intel 80286 CPU, was designed to be easy to set up and use. IBM made the unusual decision to put the power supply for the entire unit in the monitor, making use of third-party monitors impossible and limiting the usefulness of the computer if the monitor needed service (similar to the problems of the Coleco Adam years earlier).

It featured 1 MB of memory, built-in modem, an optional 30 MB hard disk, and optional sound card^[1]. IBM also released a 5.25" disk drive unit and an Adapter Card Unit (ACU) to install third-party expansion cards.^[2]

IBM PS/1 (model 2121)


Type	Personal computer
Released	(unknown)
Discontinued	(unknown)
Processor	Intel 80386sx @ 16 MHz
Memory	2 MB ~ 6 MB
OS	PC-DOS 4.01 (in ROM)

IBM PS/1 (model Unknown)


Type	Personal computer
Released	(unknown)
Discontinued	(unknown)
Processor	Intel 80486sx @ 25 MHz
Memory	2 MB ~ 6 MB
OS	MS-DOS / Windows

A later revision featured an Intel 80386sx processor running at 16 MHz.^[3]

The first PS/1 models suffered from very limited expansion capabilities, since they lacked standard ISA expansion slots. Similar to a few Tandy 1000 models, the early PS/1's had an operating system (PC-DOS 4.01) built in to ROM, rather than loading it from a hard drive.

[edit] Post "DOS in ROM" Models

On May 11, 1993 IBM introduced a "new generation" of the PS/1 line.^[4]

Later PS/1 featured standard LPX-architecture motherboards—at the expense of being no easier to set up than any other run-of-the-mill PC.

Ironically, many of these later PS/1s shipped from the factory with MS-DOS and Microsoft Windows, rather than IBM's PC-DOS and/or OS/2.

[edit] Discontinuance

The PS/1 line was discontinued in 1994 and replaced with the Aptiva line, which was architecturally very similar to the later models of the PS/1, but with a more marketing-friendly name. Aptivas were sold in the United States until early 2000, when price pressures made the line unprofitable and IBM withdrew from the retail market entirely.