FM TOWNS > MO setting guidebook for FM TOWNS

MO setting guidebook for FM TOWNS

1. Overview

The document make FM TOWNS users set up an MO drive and use it on DOS or Towns system software. It covers DIP/jumper switches settings, driver installation and transferring data between TOWNS and other system.

2. MO and HD modes

Each MO drive has a switch to select between MO(or super floppy) and HD(hard drive) modes.

An MO disc becomes identically same as a hard drive unit when the drive is set to the HD mode. You can create partitions and format them on various systems if they support standard SCSI hard drives. You can make an MO disc bootable if the system can boot from SCSI drives. Additionally, you can create FM OASYS partitions on MO discs.

However, current Mac, Windows and other PC-based systems usually cannot handle MO discs if the drive is HD mode and discs are FMR/TOWNS DOS format1. TOWNS/Linux has patches to access FMR/TOWNS DOS partitions so the source codes help you to analyze the format.

The HD mode supports 128 megabytes, 230 megabytes and 540 megabytes discs.

On the other hand, both of FM TOWNS and modern systems can access files in discs so you can transfer files among different systems when drive is set to the MO mode. However FM TOWNS requires a device driver.

The MO mode supports all types of disc that are supported by the drive(128 to 2600 megabytes) in modern systems. However, Towns system software and TOWNS DOS support 128 or 230 megabytes disc(depends on device drivers2). Windows95 and Linux for TOWNS support larger sized discs.

Please be informed that Windows NT 4.0 cannot access some MO discs formatted by older systems. Fujitsu released a tool for fixing these discs[archive]. Fujitsu MO drives with MO mode might work on FM TOWNS(I examined Buffalo MOS-S1300/USP 1300 megabytes drive unit that use Fujitsu MCD3130SS drive, and it works on TOWNS as a 230 megabytes disc drive). I have not tested other drives by non-Fujitsu companies.


H.Sato's V-TOWNS room[archive]indicates that several drivers such as SCSIDISK and FM2ATE enable PC DOS or Windows 95/98 to access the first partition of the disc.


According to H.Sato's V-TOWNS room, the driver(35MODRV.EXE) included in DOS6.2 L10 supports only 128 megabytes discs. Newer driver in DOS6.2 L10+3 supports 230 megabytes discs.

3. DIP/jumper switches

SCSI ID and HD/MO mode can be set by DIP/jumper switches. Fujitsu discloses switch settings document on their website. Those for older drives can be seen in the internet archive[archive].

4. Setting your MO drive with HD mode

  1. Set up DIP/jumper switches such that the HD mode is activated, based on above-mentioned documents. SCSI ID should be any of 0 - 3. Older TOWNS reserves SCSI ID for built-in hard drive so SCSI ID 1 - 3 would be preferable.

  2. Register MO drive by "設定-ドライブ構成" of TownsMenu, then restart system.

  3. Create partitions and format them by TownsMenu.

5. Setting your MO drive with MO mode

  1. Set up DIP/jumper switches such that the MO mode is activated, based on above-mentioned documents. SCSI ID should be set so as to avoid conflicting with hard drives in TOWNS.

  2. Prepare DOS 6 system disk(Create system floppy, or install DOS6 to hard drives3). You should copy 35MODRV.EXE if you use DOS6 system floppy disk.

  3. Add DEVICE=path-to-driver¥35MODRV.EXE /Un to CONFIG.SYS. n is SCSI ID. /Un can be added if you want to multiple MO drives. For example, DEVICE=¥35MODRV.EXE /U3 /U4 can be used when there are drives having SCSI ID 3&4.

  4. Boot from DOS6 disk.

  5. In order to format disk, execute 35MODRV.EXE drive-letter-of-mo-disc: [/P]. /P option executes low-level format then logical format. Logical format is executed when no option is designated.

  6. If you want to use MO drive on modern systems via SCSI-USB converter, SCSI ID may be set to "0".


You can set up Towns system software on DOS 6 if you have Towns system software V2.1L40 or newer. The system can handle MO discs on TownsMenu and access larger disk volumes(up to 2048 megabytes).

6. Alternate driver

BEFiS (A DOUJIN software developing circle) discloses KUMADSK driver. The driver handles PC-DOS, X68k and FM-DOS format HDD and IBM superfloppy format MO. 540MB superfloppy MO disc can be used if the driver is installed in DOS6.2.

In order to activate the driver, just add DEVICE=path-to-KUMADSK¥KUMADSK.SYS [/D] /Un (n is SCSI ID) to CONFIG.SYS instead of above 5(3) step. Icon in TownsMenu 2.1 is changed to MO drive if /D option is given.




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