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Greaseweazle - read old floppy disks


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I have a bunch of old Amiga and ST disks from back in the day. I expect most have bit rot, but I've been reading about how some folks have been surprised when their 30 year old floppies read absolutely fine, so crossing my fingers that I can still rescue some.


I couldn't find any mention of Greaseweazle here. Anyone got one?

It's an interface board that you plug a floppy drive into and it reads disks at the magnetic flux level (I think that means bypassing the drive's firmware that expects a certain format?) and hooks up to your modern computer via USB.


I've ordered a Greaseweazle F7 Lightning Plus. Not sure yet whether I have a serviceable old Amiga/ST drive that I can hook up, or even a PC one, so I need to figure that out.


Any tips appreciated :) 

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I bought a Greaseweazle F7 back in 2020 to backup a boxful of Amiga disks (nothing commercial, just my school/college/home projects).


I can't offer much information.  I just followed the instructions to use the command line tool that are on the Github page. My suggestions are probably fairly obvious:

  • It's cheaper and easier to use a standard PC floppy drive for disk imaging. You don't need an Amiga/ST drive to backup these disks.
  • You'll need to find a way to power the PC floppy drive. It was surprisingly difficult to find a 4-pin cable that would allow the Greaseweazle to power the floppy drive directly. I eventually found one on AmigaKit's ebay page.
  • If you haven't used the disks in 20+ years, you'll probably have to make several attempts to create a disk image without bad sectors. I found that disks would report around 20 bad sectors on a 1st attempt, 10 on the second, 4 on the third, and none on the 4th or 5th attempt. Even in ideal storage conditions, a small amount of dust can accumulate on the disk.




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8 hours ago, knightbeat said:
  • You'll need to find a way to power the PC floppy drive. It was surprisingly difficult to find a 4-pin cable that would allow the Greaseweazle to power the floppy drive directly. I eventually found one on AmigaKit's ebay page.


Oh. I didn't pay much attention to that bit. It looked like it was a standard 4-pin Molex connector from the F7 to the drive. Is it something more exotic?


Excited to see what I can uncover - like you, I have bits and pieces that I made when I was younger... music, art, programs, so that gives me hope.

I presume that even if a disk is not 100% readable, I might still get some whole, uncorrupted files off it, as long as the index table is ok?

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  • 2 weeks later...

I'm absolutely astonished by this thing!


I've tried snapshots on about 150 disks, mostly ST and some Amiga.

I've had about 10% with sector errors.

I try those that fail with a slower speed (not sure if that helps - it might just be the USB communication rate) and extra number of read-retries. This has captured a small proportion of the failures.

The ones that fail still create an image, so it's potluck whether there's critical data damage.


Many of these disks are 30 YEARS OLD! I expected to be only able to read a few, so this has been a wonderful archaeological dig into my teens. So impressed!


I'm using FluxMyFluffyFloppy GUI on top of Greaseweazle, which makes for a nice interface once you've figured it out. The ST disks are all different formats, but greaseweazle says when it isn't happy [either that it's ignored a viable sector or been unable to read it] so it's a good indicator just to choose a different disk layout.


One thing I'm puzzling over - I think I have some corrupted data when I load some disk snapshots into an emulator. These are disks that Greaseweazle has been happy to read without sector errors. I'm not sure what this means.

Maybe the data was corrupted when it was written years ago?

Or is it a bad read that I could fix somehow?
I think I've also seen more sector errors on commercial disks (I haven't tried so many of these). Perhaps this was some kind of copy protection?... i.e. the software would check to see that a certain sector was deliberately damaged?


I think there are options to do raw snapshots. I'm not sure if that will help at all. There's a Facebook group but I haven't seen how open they'll be to noob questions yet!

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