IBM PS/55


The Personal System/55 or PS/55 is a personal computer series released from IBM Japan in 1987.
The PS/55 is the successor to IBM 5550, but its architecture is based upon IBM PS/2. The first line-up of the series consisted of rebranded 5550 models except the Model 5570-S which was based on the PS/2 Model 80. Unlike the PS/2, most PS/55-based models have a 32-bit CPU and Micro Channel bus for the high-end business computing market. IBM Japan was hesitating to sell personal computers for consumers because the IBM JX failed. The AT bus model was released for home users in 1991.

Features

Display Adapter

The MCA video card called Display Adapter has a Japanese font containing nearly 7,000 glyphs stored in its ROM, which enables PS/2-based computers to display Japanese text without loading the font into memory. Similar to the IBM 5550, the display resolution in character mode is 1040×725 pixels in 8 colors. The graphics mode is 1024×768 pixels in 16 colors. This is the same resolution as 8514/A and XGA/A, but not compatible.
The first Display Adapter was installed in the model 5570-S, also known as the first Micro Channel machine of PS/55. It had a compatibility problem with PS/2 applications. Since the model 5550-S released in 1988, the Display Adapter II that improved the PS/2 compatibility was introduced. In the boot sequence, the Display Adapter enables VGA on the motherboard, and it passes the video signal from the motherboard to adapter's VGA connector. When using Japanese DOS, VGA is disabled, and the Display Adapter switches its video selector from VGA to own video chip. In addition, it added the 256 color mode. The adapter has 1 MB of video RAM, and 256 KB of RAM for user-defined characters.
Most PS/2-based models have compatibility with the Display Adapter II. VGA and the following display modes are supported:
  • 1040×725 pixels with 80×25 characters in 8 colors or monochrome
  • 1024×768 pixels graphics in 16 colors or monochrome
  • 1024×768 pixels graphics in 256 of 262,144 colors
Later, XGA and VGA-only models were released. These later machines cannot run the special Japanese DOS, instead requiring the use of DOS/V with software-rendered kanji.

JIS layout keyboard

The following keyboards have the PS/2 port. These keyboards have new scancode sets to support additional keys for Japanese input method.

Models

  • Tower
  • * 5570-S, T, V
  • * 5580-Y, W
  • Business Desktop
  • * 5560-W, N （Hi-end desktop）
  • * 5550-S, T, V, W, N, Y, L, R （Mainstream desktop）
  • * 5540-T （Low-end desktop）
  • For small business, home users
  • * 5530-Z, S, T, U, W
  • * 5510-Z, S, T
  • Laptop
  • * 5545-T
  • * 5535-S
  • A4 Notebook
  • * PS/55 Note
  • Rebranded IBM 5550
  • * Model G to P
YearNameModelCPUBusGraphicsCase
1987PS/555570-SIntel 80386DX 16MHzMCAD/ATower
1988PS/555550-SIntel 80386DX 16MHzMCAD/ADesktop
1988PS/555550-TIntel 80386DX 20MHzMCAD/ADesktop
1988PS/555570-TIntel 80386DX 20MHzMCAD/ATower
1989PS/555550-VIntel 80386DX 25MHzMCAD/ADesktop
1989PS/555570-VIntel 80386DX 25MHzMCAD/ATower
1989PS/555530-TIntel 80386DX 20MHzMCAD/ADesktop with integrated display
1989PS/55Z5530Z SXIntel 80386SX 20MHzMCAD/ADesktop with integrated display
1990PS/555535-SIntel 80386SX 16MHzMCAVGALaptop
1990PS/555540-TIntel 80386SX 20MHzMCAD/ADesktop
1990PS/555545-TIntel 80386DX 20MHzMCAD/AIntegrated Plasma Display
1990PS/555560-WIntel 80486 25MHzMCAD/ADesktop
1990PS/555580-YIntel 80486 33MHzMCAD/ATower
1991PS/55Z5510SIntel 80386SX 16MHzATVGADesktop
1991PS/55Z5510TIntel 80386DX 20MHzMCAVGADesktop
1991PS/55Z5510ZIntel 80286 12MHzATVGADesktop
1991PS/55note5523SIntel 80386SX 12MHzATVGANotebook
1991PS/555530-UIntel 80386SX 20MHzMCAXGADesktop with integrated display
1991PS/555530-VIBM 386SLC 20MHzMCAD/ADesktop with integrated display
1991PS/555560-WIntel 486SX 25MHzMCAD/ADesktop
1991PS/555580-WIntel 486SX 25MHzMCAD/ATower
1992PS/555551-WIntel 486SX 20MHzMCAXGADesktop
1992PS/55Z5530-UIBM 386SLC 20MHzMCAXGADesktop with integrated display
1992PS/555530-WIntel 486SX 20MHzMCAXGADesktop with integrated display
1992PS/555560-NIntel 486DX2 66MHzMCAXGADesktop
1992PS/55note9552-YIBM 486SLC 25MHzMCAVGANotebook
1992PS/5595 XP 486Intel 486DX 50MHzMCAXGATower
1993PS/555521-YIntel 486SX 33MHzMCAD/A / SVGADesktop
1993PS/555551-LIBM 486DLC2 66MHzMCAD/A / XGADesktop
1993PS/555551-NIntel 486DX2 66MHzMCAD/A / XGADesktop
1993PS/555551-YIntel 486SX 33MHzMCAD/A / XGADesktop
1993PS/55 Server95Intel Pentium 66MHzMCAXGATower
1994PS/555530-LIBM 486DLC2 66MHzMCAD/A / XGADesktop with integrated display
1994PS/555551-RIntel 486DX2 66MHzMCAD/A / XGADesktop

Competitors