IBM 5550


IBM 5550 is a personal computer series that IBM marketed in Japan, Korea, Taiwan and China in the 1980s and 1990s, for business use customers. In Japan, it was introduced in 1983 and promoted as "Multistation 5550" because it had three roles in one machine: a PC, a word processing machine which was traditionally marketed as a machine different from a PC in Japan, and an IBM-host attached terminal.

General

The IBM PC that had been marketed by IBM since 1981, using Intel 8088, was not powerful enough to process the far eastern languages of Japanese, Korean and Chinese. Nor was the resolution of IBM PC's display high enough to show the complex characters of these languages.
The IBM 5550 was first introduced in Japan in March 1983, using Intel 8086 microprocessor and was called "Multistation 5550" because it had three roles in one machine: a PC, a word processing machine which was traditionally marketed in Japan as a machine different from a PC, and an online terminal.
After the Japanese 5550 models, Korean, Traditional Chinese and Simplified Chinese models were also introduced. IBM 5550 initially used its own architecture, but, later since 1987, was changed to use IBM Personal System/2's Micro Channel Architecture, being renamed as Personal System/55.
In Japan, Kiyoshi Atsumi, a film actor, was used to promote the 5550. IBM later introduced IBM JX for home users in Japan, Australia and New Zealand, and DOS/V for both business and home users in Japan.

Features

The 5550 was originally planned as a terminal with a combination of word processing and personal computing targeted for Japanese computer market. To display 24 dots Mincho kanji typeface which was also used in many Japanese electrical word processors, the 5550 had high display resolution such as a 1024×768 pixel graphic screen. The 5550 read a display font from an external storage to support multilingual include Japanese, Chinese, and Korean language.
The 5550 provided below three roles:
The original Bunsho Program and emulators booted from a floppy disk without Nihongo DOS. They used a proprietary disk format which couldn't be read from Nihongo DOS, so users had to replace floppy disks or set the boot partition to switch between two programs. Also, they had to use a conversion program to exchange data. Later, they were ported for Nihongo DOS, and functions were gradually implemented. The 3270 Kanji Emulation was superseded by the Nihongo 3270 PC released in October 1983, and the 5250 Kanji Emulation was superseded by the Nihongo 5250 PC in September 1984. The Bunsho Program was also superseded by the DOS Bunsho Program in May 1986.
The first generation of IBM 5550 had up to three 5¼ inch double-density floppy drives because the Bunsho Program used three floppy disks; program disk, font disk, and user's data disk. Later, two-drive models contained a font ROM card as other Japanese personal computers did.

Development

Yu Kawara of IBM Fujisawa Development Laboratory planned the terminal with a combination of word processor and personal computer, called the Multi-functional Workstation, and he proposed it at the headquarter in March 1981. The development team was founded as an Independent Business Unit.
The team set goals for IBM 5550 that the machine was usable for both word processing and personal computing on the same architecture at least 3-5 years. They tried to build the 5550 from the IBM Displaywriter System 6580, the English word processor developed in Austin office in 1980, and the IBM Personal Computer developed in Boca Raton office, but it was difficult to combine different types of machines.
Considering price–performance ratio and continuity of an architecture, the team examined processors chosen from Intel's and other manufacturers. The IBM PC used an Intel 8088, but the 5550 employed an Intel 8086 because bus speed largely influenced for performance of the machine which had high display resolution.
To gain an advantage over competitors in Japanese word processing, 24 pixel font models render characters in a box of 26×29 pixels, and the total display resolution is 1066×725 pixels calculated with box width by 41×25 text. 16 pixel font models render characters in a box of 18×21 pixels, and the total display resolution is 738×525 pixels. The 5550 had one more column than 40 columns of usual Japanese computers, which enabled line breaking.
on PS/55
For personal computing, the Nihongo DOS K2.00 had been developed by Microsoft. It was a Japanese localization of MS-DOS 2.0 followed to Toshiba's PASOPIA 16. The Nihongo DOS bundled the Microsoft BASIC interpreter specialized for IBM 5550. Programming languages and the Japanese version of Multiplan were also provided.
The team didn't consider the machine was used for online communication, but they realized its importance during the development. They decided to add a role of a terminal in January 1982. This change extended the development term. In May 1982 Business Show, IBM Japan only displayed the IBM PC as a reference material. They unveiled the development of 5550 in fall 1982.
IBM Japan didn't have a factory for mass production of personal computers, so the production of 5550 was outsourced to some companies. System units, hard disks, and monitors were manufactured by Matsushita Electric Industrial, printers by Oki Electric Industry, and keyboards by Alps Electric.

Models

In Japan, Multistation 5550 competed against:
BYTE in 1983 speculated that "we may soon see a similar machine here in America". Describing the 5550 as "a true workstation", the magazine envisioned the computer as filling the "considerable gulf above the PC", and a rival to the IBM System/36 minicomputer. It praised the 5550's "unprecedented" combination of kanji support with high-end word-processing capability, and reported that in Japan an ecosystem of vendors providing products for the computer was forming. The magazine concluded that "if the American PC is any precedent, the market should soon be filled with 5550 software".