FM Towns:Using Hard Drives

FM Towns used SCSI hard drives with the DOS sector partition limit at 120MB.
Most of these drives are likely dead or dying, really loud, and consume a lot of power.
Modern people are inclined toward hard drive emulators which work extremely well.

The truth is that most FM Towns games don't require a hard drive. Some of the later DOS ports might.
But generally, you can just put the CD in and play most games that way. Specifically, arcade games don't require HDD.

Towns used SCSI for their HDD format and any SCSI hard drive emulators will work.
Generally, HDD emulators can't seek as fast as a mechanical HDD but they're also not 30 years old and dying.
There are a few tested options.

• SCSI2SD 5.2 or later will work very well with FM Towns with default settings.
• BlueSCSI which is open source at the hardware and software level works well with FM Towns.
  
  

Generally, it is encouraged to use an External HDD for a Tower model but you could opt in for an internal solution.
In the next section you might determine that isn't practical and opt-in for an external HDD at least for towers.

Internal HDD

So you opted in for an internal HDD. You will require the special HDD tray which occasionally appears for sale on yahoo. It sometimes comes with desktop computers for sale.

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  HDD Tray near red arrows.

To access this tray just requires removing the top lid which isn't that bad to do for desktops.
FM Towns used a proprietary-ish pinout for the internal SCSI connector. It is 50 pins but they integrated 5V and 12V and GND pins in different spots.
Plugging in a HDD straight into it will destroy the HDD and damage the PC. Use the HDD Tray if you have it.

For the Tower models, the internal hard drive location is extremely inconvenient and requires severe disassembly to access as it's near the power supply.
Accessing these requires severe disassembly to access SD cards or HDD.

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  Gen 2/3/4 Towers have an Internal SCSI connector on the left side. Very inconvenient to access this.

Labo-san posted the pinout on his website and instructions for making a custom cable if the warnings are still ignored.
His project used a Magneto-Optical drive but any SCSI device such as HDD will be fine.

External HDD

Using an external HDD emulator is a very good idea as it works for all FMT models and is more convenient for moving around.
It's also easier to access the SD card if required.
You will be required to get a SCSI50 to IDC50 Cable which are available online.
Gen 1 Towers don't have SCSI controller on board and require a very specific expansion card for SCSI that is needed to use HDD. Sort of difficult to find.

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  SCSI1 to IDC50 Cable connected to SCSI2SD on a CX20