Floppy emulation on the Commodore Amiga

Well for some unknown reason the floppy drive in my Amiga just stopped working.  I managed to find a drive out of an Amiga 500, but it too didn’t work.. I really don’t know if it is the controller or if it is the drives.  And I’m hesitant to sink £100 into a machine that for all I know could have a dead controller.

So this means while I do have the Compact Flash working as a hard disk, I am unable to load an old favorite Captain Blood.  Maybe I am more of a sucker for the Jean-Michael Jarre resampled sound track ethnicolor. Or maybe there is just something redeeming about blowing up random planets.

Then while digging around DICE, I looked at its examples, and one of them was the exec_dev one, FMS a floppy emulator!  I built the example installed the driver, and using it resulted in a nice crash in both AmigaDOS 2.04 and 2.1 .. I had to wonder if this was more so geared to AmigaDOS 1.3 ..?  A bit of googling around and I found an updated version, fms_20.lha.  Installation is a little cumbersome as you have to manually copy in the device driver, and then setup a mountlist describing the devices in question, which really reminded me the “fun” of 4.3 BSD’s disktab.

Another weird thing is that AmigaDOS 2.1 has the FastFileSystem driver built in, so I had to remove those lines…

Using an ADF I found (since there is no way I can read the physical disk now..) I was able to use DMS to make an image on an emulator, copy it onto the flash, then re-DMS it out on the emulated floppy diskette.  Thankfully this game doesn’t use any weird custom filesystem so it was easy enough to mount the disk, and run the game from the emulated floppy.. Or at least launch it.  Trying to use it however resulted in the game just crashing.

Some more digging with a hex editor showed that the string “DF0:” was strewn all through the executable, so a few minutes, and I changed them all to “FF7” and now the game plays properly.

Captain Blood on my Amiga 600
Captain Blood on my Amiga 600

I wonder if it is possible to load the bootblock from one of these custom filesystems then use a virtual void pointer in DICE C, and execute the bootblock directly?  I’ll have to experiment.

Author: neozeed

I live in SE Asia, doing generic work, enjoying my life & family

4 thoughts on “Floppy emulation on the Commodore Amiga”

      1. 🙂
        I have recently scored a fully loaded Atari TT030. It looks like new, it was refurbished by the company who sells them like new. It had a sealed, unopened keyboard and mouse. Too bad I can’t post a photo in the comments.

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