IBM PS/55
| Industry | Personal computers |
|---|---|
| Predecessor | IBM 5550 |
| Founded | 1987 |
| Founder | IBM Japan |
| Successor | IBM PC 300/700 series (Business Desktop line) |
| Headquarters | Tokyo , Japan |
Area served | Japan |
| Products | PS/55 personal computers |
| Owner | IBM Japan |
| Parent | IBM |
The PS/55 series represents a line of personal computers introduced by IBM Japan in 1987.
Serving as the follow-up to the IBM 5550, the PS/55 system architecture draws from the IBM PS/2. The initial models were predominantly updated versions of the 5550, with the exception of the Model 5570-S, which was derived from the IBM PS/2 Model 80. Unlike the PS/2 series, a majority of PS/55 computers utilized 32-bit processors (Intel 80386 or Intel 80486) alongside a Micro Channel (MCA) bus, aiming at premium business computing segments. Following the unsuccessful launch of the IBM JX, IBM Japan initially refrained from entering the consumer PC market; however, an AT bus variant targeting home users appeared in 1991.
Display Adapter
The MCA video card, termed the Display Adapter, contains a Japanese font set with nearly 7,000 glyphs embedded in ROM, allowing native Japanese text rendering without requiring font loading into RAM. It offers character mode at a resolution of 1040×725 pixels (80×25 characters) in 8 colors and a graphics mode at 1024×768 pixels with 16 colors—comparable to 8514/A and XGA/A standards but lacking direct compatibility.
The original Display Adapter debuted in model 5570-S, marking the first PS/55 machine utilizing Micro Channel technology; however, it exhibited compatibility challenges with PS/2 software. The enhanced Display Adapter II was introduced with model 5550-S in 1988, improving compatibility with PS/2 systems. During startup, it activates VGA on the motherboard and routes video output through its VGA connector; under Japanese DOS environments, it disables VGA and switches to its own video chipset. This iteration added a 256-color mode (1024×768 pixels selectable from 262,144 colors), supported by 1 MB of video RAM and an additional 256 KB for user-defined characters.
Most PS/2-based units are compatible with Display Adapter II and support VGA along with these display modes:
- 1040×725 pixels character mode (80×25 characters) in either 8 colors or monochrome
- 1024×768 pixels graphics mode with 16 colors or monochrome
- 1024×768 pixels graphics mode featuring 256 colors chosen from a palette of 262,144
Subsequent models limited to XGA and VGA required DOS/V for Japanese text display as they lacked native support for specialized Japanese DOS.
JIS layout keyboard
These keyboards connect via PS/2 port and utilize updated scancode sets (81h, 82h, 8Ah) to accommodate additional keys necessary for Japanese input method:
- 5576-001 - Layout identical to the original 5550 type 1 (5556-001) keyboard.
- 5576-002 - Japanese configuration modeled after the 101 Enhanced keyboard featuring mechanical switches by Alps Electric Co..
- 5576-003 - A compact variant of the 5576-002 design.
- 5576-A01 - Keyboard conforming to OADG standards.
Models
- Tower Series
- Models 5570-S, T, V (Initial releases; notably, the first PS/55 model, 5570-S lacked English PC DOS and OS/2 compatibility)
- Models 5580-Y, W (Later tower iterations)
- Business Desktop (Forerunner to the IBM PC 300/700 series)
- Models 5560-W, N (Premium desktop options)
- Models 5550-S, T, V, W, N, Y, L, R (Standard desktop configurations)
- Model 5540-T (Entry-level desktop)
- Small Business and Home User Systems
- Models 5530-Z, S, T, U, W (Desktop units featuring integrated displays; precursors to PS/V Vision)
- Models 5510-Z, S, T (VGA-equipped models; predecessors to PS/V)
- Portable Computers
- Model 5545-T (Equipped with integrated plasma display)
- Model 5535-S (First model shipped with pre-installed DOS/V)
- A4 Notebook Line
- PS/55 Note (Ancestor of the ThinkPad, compatible with AT or MCA bus)
- Rebranded Versions of IBM 5550
- Models G through P (Produced between 1987 and 1991)
| Year | Name | Model | CPU | Bus | Graphics | Case |
|---|---|---|---|---|---|---|
| 1987 | PS/55 | 5570-S | Intel 80386DX at 16MHz | MCA | D/A | Tower |
| 1988 | PS/55 | 5550-S | Intel 80386DX at 16MHz | MCA | D/A | Desktop |
| 1988 | PS/55 | 5550-T | Intel 80386DX at 20MHz | MCA | D/A | Desktop |
| 1988 | PS/55 | 5570-T | Intel 80386DX at 20MHz | MCA | D/A | Tower |
| 1989 | PS/55 | 5550-V | Intel 80386DX at 25MHz | MCA | D/A | Desktop |
| 1989 | PS/55 | 5570-V | Intel 80386DX at 25MHz | MCA | D/A | Tower |
| 1989 | PS/55 | 5530-T | Intel 80386DX at 20MHz | MCA | D/A | Desktop with integrated display |
| 1989 | PS/55Z | 5530Z SX | Intel 80386SX at 20MHz | MCA | D/A | Desktop with integrated display |
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Competitors
See also
Further reading
External links
- PS/55, Japanese PS/2 Accessed September 28, 2022