The following information is up to date as of October 2023.
The purpose of this document is to outline how to get a BlueSCSI / ZuluSCSI modern microSD to SCSI emulator to work with the FM Towns. This document has only been tested on the FM Towns II (my unit is the Fresh T) but should work on most 486 or better desktop computers.
Also, unlike the X68000, getting a SCSI hard drive connected to the FM Towns is not required. Almost all the games run from CD's (even if you install the game to the hard drive, the CD is still needed for the CD music tracks) So consider this more of a nice to have than a must have.
In the future I suspect we'll see CD-ROM replacements for the FM Towns which will make this even less relevant.
PreReq:
- Working FM Towns computer - SRAM battery inside must have been replaced
- FM Towns Keyboard
- FM Towns joystick (I use an SNES to X68000 adapter with an SNES controller)
- BlueSCSI (https://bluescsi.com/) or ZuluSCSI (https://zuluscsi.com/) - make sure to get the external version (DB25 RP2040 based) as it's easier to keep the software updated without needing to take the computer apart.
- 8GB or bigger MicroSD card (smaller cards might not work)
- SCSI external cable to connect between your FM Towns and 25 pin connector
The cable is the most difficult part. The FM Towns uses the original SCSI-1 CN-50 connector on the back. You will require a cable that converts from your FM Towns external SCSI port to the DB25 port on the SD device. I also had to get a DB25 gender changer to go between my ZuluSCSI and SCSI-1 cable.
Some things to keep in mind:
- FM Towns keeps its boot order in SRAM
- Unlike any other computer, mapping between drive partitions and drive letters are also kept in SRAM (Imagine C: and D: partitions you defined in FDisk on a PC had to keep the mapping in BIOS; i.e. Drive 0, partition 0 is C:, drive 0, partition 1 is D:, etc.) If this information is lost, the computer will not boot! So, when you download a drive image from the Internet, and try to use it on FM Towns, you must define the partition map in SRAM for it work.
- If your SRAM battery (CR2032) is dead; this mapping is lost after each reboot and needs to be recreated
SD card setup:
- Download the FM Towns boot disk image (https://nfggames.com/forum2/index.php?topic=6954.msg47665#msg47664)
- Format the microSD as FAT32 (https://www.retrorgb.com/sdformat.html)
- rename the image file HD3.hda
Note: The filename specifies the boot disk image is a hard drive with SCSI ID 3. If you have an internal SCSI hard drive, it has SCSI ID 0. You can disconnect the internal drive and set this file to ID 0 (You don't have to worry about SCSI termination with the FM Towns internal drive disconnected) For the rest of this document, we assume that your HD is SCSI ID 3. If it's something else, change accordingly the instructions.
- Download FM Towns 2.1 install CD image. I downloaded [OS] Towns System Software v2.1 L51 [CD].7z from (https://archive.org/details/neo_kobe_fujitsu_fm_towns_2016-02-25-repack_20200803)
- Rename the CUE file to CD1.cue and IMG file CD1.bin. Edit the CD1.cue file and make sure the first line is updated to read:
FILE "CD1.bin" BINARY
This will make the SCSI device also define a SCSI attached CD-ROM drive at SCSI ID 1 with the FM Towns OS 2.1 install CD loaded in it. Next, we need a way to kick off the SCSI CD-ROM boot. Ideally, you hold A and B buttons on the joystick controller and press the reset button to get a boot menu selector. You select SCSI device with ID 1 (navigate with A/B buttons in the boot loader). Then select exit and it should boot.
This did not work for me. I had to use an alternative boot loader to force the external CD-ROM to boot. The process is as following:
- Download the SCSI boot loader HDIMAGE.BIN from here (http://ysflight.in.coocan.jp/FM/towns/bootloader/emergency_hd_e.html)
- Rename HDIMAGE.BIN to HD4.bin
Modifying the SRAM:
Ain't it wild? You now have 3 SCSI devices attached to the computer! CD-ROM on SCSI ID 1, Hard drive image on SCSI ID 3, and boot loader on SCSI ID 4. We need to boot the install CD.
- Use the joystick method described above to force SCSI ID 4 to boot
- When the boot loader menu comes up, select Boot from CD-ROM to have it load the FM Towns OS install CD.
- Alternatively, you can burn the CUE/BIN file to a CD-R and boot that.
- Follow these instructions to update your SRAM partitions and default boot device (https://monochromeeffect.org/JVCC/2020/03/23/towns-os-hdd-installation/)
Note: There's a utility in the root of the CD that gives you the command prompt. You than cd into the EXE directory and run setup.exe as described in the above website. The drive image you downloaded has 10 partitions. So you need to define drive D: to drive M: and then set the default boot drive to ID 3 (it's the next menu item under the RS-232 option)
When you get out of the tool, reboot and the computer should boot FM Towns OS 2.1 from the hard drive image found at SCSI ID 3.
If you find mistakes in this wiki - please update.