IBM PS/1
| Company type | Consumer home computer |
|---|---|
| Industry | Computer hardware |
| Predecessor | IBM PCjr |
| Founded | 1990 |
| Defunct | September 1994 |
| Successor | IBM Aptiva |
Area served | Worldwide (notably United States and Europe) |
| Products | Personal computers |
The PS/1 series, referred to as the PS/1000 in select European regions, represents IBM's re-entry into the home computing sector in 1990, following a five-year hiatus after the IBM PCjr. This line was eventually replaced by the IBM Aptiva in September 1994.
Position within IBM's PC Portfolio
Designed primarily for novice users, the PS/1 was retailed through consumer electronics outlets and competed with brands such as Compaq, Hewlett-Packard, and Packard Bell. Models sold in the United States featured an integrated modem that facilitated access to IBM's online support platforms via collaborations with Prodigy and Quantum Computer Services.
In contrast to IBM’s business-oriented PS/2 lineup, the PS/1 utilized architecture more akin to the AT and compatible systems. It incorporated standard components like ISA slots, conventional VGA graphics, and IDE interfaces. Initial releases contained custom hardware and a ROM-based version of IBM's PC DOS with a graphical shell, though users could install alternative DOS versions and transfer the shell to the hard drive. Subsequent versions introduced the "Rapid Resume" feature, which supported standby and hibernation functionalities.
Throughout its lifespan, the PS/1 was available in multiple chassis designs, including:
- 2011 – A proprietary configuration with the power supply housed within the CRT monitor
- 2121 – Similar proprietary case offering up to two ISA expansion slots
- 2123 – A limited-run model utilizing the IBM PS/2 model 30 enclosure, equipped with three ISA slots
- 2133 – Desktop unit named after its slot and drive bay count (3x3)
- 2155 – Larger desktop case (5x5), featuring a 5.25" drive bay
- 2168 – Tower configuration (6x8), accommodating multiple expansion slots and various bays including 5.25" drives
2011 Series
The inaugural PS/1 model (2011) was powered by a 10 MHz Intel 80286 processor and prioritized user-friendly setup. Memory options included either 512 KB or 1 MB onboard RAM, expandable up to 2.5 MB through proprietary modules. U.S. versions incorporated a built-in modem, and storage options began with an optional 30 MB hard drive later upgraded to 40 MB. IBM provided an optional $169 Adapter Card Unit (ACU) expansion box that allowed installation of up to three 8/16-bit ISA cards. Additionally, a $995 CD-ROM drive based on a Western Digital SCSI controller could be mounted underneath the main unit. Early iterations lacked standard ISA slots unless paired with the ACU, which limited expandability; however, users could easily add up to three memory modules priced at $199 each (512 KB). The initial configurations were:
- $999 VGA Monochrome (640x480), 512 KB RAM
- $1,499 VGA Color (640x480), 512 KB RAM
- $1,699 VGA Monochrome (640x480), 1 MB RAM, 30 MB hard disk
- $1,999 VGA Color (640x480), 1 MB RAM, 30 MB hard disk
2121 Series
Maintaining a similar chassis design, the 2121 models introduced up to two ISA slots within the case. Memory capacity expanded from 2 MB up to 6 MB using a proprietary 4 MB module. Higher-tier versions were equipped with an Intel 80386SX CPU running at either 16 or 20 MHz.
Highlighted configurations included:
| Model | US Price | Processor | ISA Slots | RAM | VRAM | Hard Disk | Serial / Modem |
|---|---|---|---|---|---|---|---|
| 2121-C42 | $1,699 | Intel 80386SX @ 16 MHz | None | 2 MB | 256 KB | 40 MB IDE | 2400 baud modem |
| 2121-B82 | $2,199 | Intel 80386SX @ 16 MHz | Two | 2 MB | 256 KB | 80 MB IDE | 2400 baud modem |
| 2121-C92 | Unknown | Intel 80386SX @ 16 MHz | None | 2 MB | 256 KB | 129 MB IDE | 2400 baud modem |
| 2121-G42 | Unknown | Intel 80386SX @ 20 MHz | None | 2 MB | 256 KB | 40 MB IDE | 2400 baud modem |
(Additional variants offered diverse combinations of memory and hard disk capacities.)
Display Units: The DC power supply was integrated into IBM’s monitors, which restricted compatibility with third-party displays and complicated service procedures. Some systems shipped with greyscale VGA monitors; enthusiasts occasionally rewired pinouts to enable use of alternative monitors.
'"DOS in ROM": Early PS/1 units came with PC DOS version 4.01 embedded directly into ROM rather than loading from disk storage. This ROM-based environment launched a "4-quad" interface providing access to help resources, software applications, online services, and file management tools. Users had the option to upgrade their systems to boot from hard drives using DOS versions up to MS-DOS 6.22, which also supported running the "4-quad" interface from disk if preferred.
Model 2133
The 2133 series of PS/1 systems came in multiple hardware setups, mainly distinguished by their processor model, memory size, video controller, and hard disk capacity.
| Model | CPU | RAM | SIMM | Video chip | VRAM | Hard Drive | Notes |
|---|---|---|---|---|---|---|---|
| 2133-111 | Intel 80386SX @ 25 MHz | 2 MB | 2×72 Pin FPM | Cirrus CL-GD5410 | 256 KB | 80 MB IDE | |
| 2133-711 | Intel 80386SX @ 25 MHz | 2 MB | 2×72 Pin FPM | Cirrus CL-GD5410 | 256 KB | 85 MB IDE | |
| 2133-811 | Intel 80386SX @ 25 MHz | 4 MB | 85 MB IDE | ||||
| 2133-13T | Intel 80486SX @ 25 MHz | 4 MB | 2×72 Pin FPM | 256 KB | 129 MB IDE | ||
| 2133-?43 / ?50 / ?53 | Intel 80486SX @ 20–25 MHz | 4 MB | 2×30 Pin FPM | 512 KB | 129 MB IDE | ||
| 2133-652 | Intel 80486SX @ 33 MHz | 4 MB | 4×72 Pin FPM | Cirrus CL-GD5424 | 512 KB | 171 MB IDE | |
| 2133-575 | Intel 80486DX @ 33 MHz | 4 MB | 4×72 Pin FPM | 512 KB | 170 MB IDE | ||
| 2133-594 | Intel 80486DX2 @66 MHz | 4 MB | 4×72 Pin FPM | 512 KB | 253 MB IDE | ||
| Canada models (E11/F11) | Intel 80386SX @25 MHz | 2 MB | 2×72 Pin FPM | Cirrus CL-GD5424 | 512 KB | 85 MB IDE | |
| Canada models (E43/F43/E53/F53) | Intel 80486SX @20–25 MHz | 2 MB | max.8×30 Pin FPM | Tseng ET4000 | 512 KB | max.129 MB IDE |
This series encompassed processors from the Intel 80386SX up to the advanced Intel 80486DX2, with memory options ranging from fixed onboard RAM to expandable SIMM modules. Graphics solutions incorporated Cirrus Logic and Tseng Labs chips, delivering performance suited for professional applications. Storage capacities varied considerably to accommodate different user requirements. Additionally, specific Canadian versions were tailored to serve both English and French-speaking customers.
Model 2168
European Variants
| Model | CPU | RAM | Hard Drive | |
|---|---|---|---|---|
| 2168-452 | Intel 80486SX @25 MHz | 2 MB | 85 MB IDE | |
| 2168-463 | Intel 80486SX @33 MHz | 4 MB | 130 MB IDE | |
| 2168-473 | Intel 80486DX @33 MHz | 4 MB | 130 MB IDE | |
| 2168-483 | Intel 80386DX @50 MHz | 4 MB | 129 MB IDE | |
| 2168-493 | Intel 80486DX2 @66 MHz | 4 MB | 130 MB IDE | |
| 2168-552 | Intel 80486SX @25 MHz | 4 MB | 129 MB IDE | |
| 2168-584 | Intel 80486DX2 @50 MHz | 4 MB | 253 MB IDE | |
| 2168-594 | Intel 80486DX2 @66 MHz | 4 MB | 253 MB IDE |
United States Variants
| Model | CPU | RAM | Video chip & VRAM | Hard Drive | |
|---|---|---|---|---|---|
| 2168-BB1 | Intel 80486DX2 @66 MHz | 4 MB | CL-5428,1 MB | 420 MB IDE | |
| 2168-US1 | Intel 80486DX2 @50 MHz | 4 MB | CL-5428,1 MB | 340 MB IDE | |
| 2168-SR1 | Intel 80486SX @33 MHz | 4 MB | CL-5428,1 MB | 253 MB IDE | |
| 2168-38C | Intel 80486DX2 @50 MHz | 4 MB | CL-5428,512 KB | 340 MB IDE | |
| 2168-57C | Intel 80486DX2 @66 MHz | 8 MB | CL-5428,1 MB | 720 MB IDE |
Additional US editions included Consultant, Expert, Essential, and Investor configurations. These ranged from Intel 80486SX processors running at 33 MHz to DX2 variants at up to 66 MHz. Memory sizes spanned from four to eight megabytes. Graphics hardware featured either CL-5426 or CL-5428 chips with VRAM capacities between half a megabyte and one megabyte. Hard drives varied from moderate to large capacities between approximately170 and420 megabytes of IDE storage.
Models Following "DOS in ROM"
On May 11, 1993, IBM introduced an updated generation of the PS/1 series, now equipped with standard LPX motherboards. These subsequent versions frequently came pre-installed with MS-DOS and Microsoft Windows, replacing IBM's own PC DOS or OS/2 to better match consumer preferences. Notably, an early 2133 unit was shipped with OS/2 2.1, illustrating IBM's approach to target OS/2 toward premium-tier systems.
End of Production
IBM discontinued the PS/1 lineup in 1994, replacing it with the Aptiva range. While the Aptiva shared a similar underlying design, it benefited from enhanced promotional efforts. The Aptiva remained available in the U.S. market until the early 2000s; however, mounting price competition eventually made the series unprofitable, prompting IBM to withdraw from retail desktop PC sales.