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F > FUJITSU  > FM Towns

FM Towns

Untitled Document


FM TOWNS is a personal computer released by Fujitsu Japan. They are sold only in Japan. The first model was released at Feb. 1989, and the last model was released at Jul., 1997. The computer is a 386-based archtecture, but is INCOMPATIBLE with IBM-PC architecture. They are mainly used in home, and in schools. The specifications --- improved garaphics and sounds, built-in bootable CD-ROM drive, and 386 DOS Extender causes impressive games and creative tools. The specifications are especially suitable for porting AMIGA/PC-VGA games into Japanese. Around 500 thousands sets of the computer were sold in japan.


CPU:intel i386SX or higher
memory:1 megabyte or more, most of Towns games requiring 2 megabytes memory.
graphics: 640x480 at 256 of 16M colors, 640x480 at 16 of 4096 colors, and 320x240 at 32768 colors screens are primarily used.
sounds: Yamaha YM-2612 4-operator/6-voice stereo FM sound chip, and Ricoh RF5C68 8-bit/8-voice stereo PCM sound chip.
built-in diskette drive: 1 or 2 3.5'' 1.25 megabyte drives. The rotational speed thereof is 360 rpm, and volume per sector is 1024 bytes.
built-in CD-ROM drive:one x1(or faster) CD-ROM drive.
storage interface:SCSI 1.
ports: 1 serial, 1 parallel, keyboard, 2 ATARI joystick ports (1 of them is usually used for a mouse), microphone, headphone, Line in/out, monitor
OS:Towns OS is primary-use system. MS-DOS 3.1/5.0/6.2, Windows 3.0/3.0MME1.0/3.1/95, NetWare, and Linux for TOWNS are also ported.


In 1981, IBM released IBM PC. The computer had widely spread in offices. However, the architecture was not popular in Japanese offices. Japanese language uses Kanji letters, which requires at least 12x12 pixels area for displaying a letter. PC's CGA is too poor to handle Japanese. To handle Japanese language sufficiently, Japanese computer companies were developped other x86-based computers having 640x400 video adapters. NEC's PC-9801 archtecture, which was released at 1982, was the most poplular one. In late 1980's, at least 70% of the 16/32 bit computers are PC-9801 computers. They were spread in home, and a number of games were released for this architecture.

The PC-9801 computers were wide-spread, however, they have poor graphics (640x400 at 16 of 4096 colors) and sounds (4-operator/3 voice monoral FM sounds). Therefore, like as AMIGA in US, a computer having improved graphics and sounds was considered to overcome the PC-9801 in the home-use field. For example, SHARP's X68000 computers, released at Mar., 1987, became popular among people who like action/shooting games.

Fujitsu, which had been released a best-seller 8-bit home computer "FM-7" in early 1980's, was decided to release a new home computer. After FM-7 was overcome by NEC's PC-8801 computer, Fujitsu got a useful experience that the number of usable softawre packages are important to sell computers. Therefore, in order to acquire usable software immediately, the archtecture of the new computer is set to be based on Fujitsu's "FMR50" architecture. The FMR50 architecture, released at 1986, is another x86/DOS-based computer having a constitution similar to NEC's PC-9801. The computers were sold in moderately in Japanese office, especially in Japanese goverment office. There have released hundreds of software packages for FMR, including Lotus 1-2-3, Wordstar, Multiplan, and dBASE III.


Many people who natively use European languages may have a question "Why the name of the computer is plural-form, although the name defines a single computer?". The reason will be described hereinafter.

In those days, Fujitsu provided a codename named after nobel-prized scientist for each PC products. The codename of the first model of FM TOWNS is "Townes", named after Charles Hard Townes (1964, phisics), an inventor of maser. The product name came from the codename, but the word "TOWNES" can be pronounced as Tau-Ness. Accordingly, to be pronounced as "Townz", the letter "e" was removed from the codename.

The word "FM" is an acronym from "Fujitsu Micro".


Bootable CD-ROM drive

All models of FM TOWNS have built-in CD-ROM drives. To boot a system from CD-ROM disk, FM TOWNS has a "hidden C:" ROM drive. The C: drive of FM TOWNS is a ROM drive, in which a minimum MS-DOS system, CD-ROM driver and MSCDEX.EXE are installed. This minimal DOS system works first, and the DOS system reads and executes TownsOS IPL stored in CD-ROM disk then. The TownsOS CD-ROM disk has the IPL, MS-DOS system(IO.SYS), DOS extender, and Towns API (TBIOS).

It should be strongly insisted that Fujitsu allowed the software developers to record minimum TownsOS system in their CD-ROM with very low license fee. Accordingly, the software developers could sell their software recordeded in bootable CD-ROM disk. The FM Towns users can play CD-ROM-based games without any boot diskette, even if they have no hard disk drives.

32bit based system

If you are/were a 16bit DOS programmer, you would remember 64-kilobyte segment nightmare. Since the processor only can access 64 kilobytes of memories linearly, it is difficult to handle a large size of data such as a graphic data or PCM sound data.

TownsOS solves this problem by using Phar Lap DOS Extender (RUN386.EXE), which enables DOS to execute i386 32-bit code.


FM TOWNS TBIOS supports so many graphics modes. Following table shows the specification of each graphic mode.

mode #vertual screen sizedisplaying screen size colorsHSYNCmode # of overlappable screen
1640x819640x40016/409624 kHz1, 2
2640x819640x20016/409624 kHz1, 2
31024x512640x48016/409631 kHz3, 5, 10
41024x512640x40016/409624 kHz4, 6
5256x512256x2563276831 kHz3, 5, 10
6256x512256x2563276824 kHz4, 6
7256x512256x2403276815 kHz(interlace)7, 9
8256x512256x2403276815 kHz8, 11
9512x256360x2403276815 kHz(interlace)7, 9
10512x256320x2403276831 kHz3, 5, 10
11512x256320x2403276815 kHz8, 11
121024x512640x480256/16M31 kHznone
131024x512640x400256/16M24 kHznone
141024x512720x480256/16M15 kHz(interlace)none
15512x512320x4803276831 kHznone
16512x512320x4803276815 kHz(interlace)none
17512x512512x4803276831 kHznone
18512x512512x4803276815 kHz(interlace)none

As shown in the above table, FM TOWNS can overlap 640x480/16 screen on 320x240/32768 screen. It is extremely suitable for porting AMIGA/PC games with Japanese translation. That is, 320x240/32768 screen is used for displaying high-color graphics, that may be equivalent to VGA 320x200/256 or AMIGA 320x200/4096 screen, while the overlapped 640x480 screen is used for displaying Japanese text, which is not requires so many colors but requires higher resolution.

The overlapping feature is further used for a sprite function (one 256x240 screen are used for displaying sprites, and other one screen serves as a background screen), which is suitable for creating action/shooting games, even if the function is poorer than that of X68000.


Author: Jiro Kita and his website.

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