Yamaha Disklavier Floppy Disks

[confusedlimes]

Hello Everybody!

I've been backing up and restoring floppy disks for Yamaha player pianos (Disklaviers) from the 1990s. These disks have some basic copy protection. Yamaha says the “master boot record” is missing—basically, the first sectors of the disk are missing, and Yamaha provides its own proprietary metadata file.

Hobbyists have made software to read these disks over the years, and they work 90% of the time. But sometimes, they don't copy well using these tools, even though the disks themselves still play in the piano. I've been trying to copy these difficult disks and reproduce them using a Greaseweazle v4.1. Some of these disks are clearly decayed and noisy, and probably aren't reading through hobbyist software because of actual damage, even though they still play.

I've been imaging the disks as an hfe, and this seems to work when I reproduce it: gw read ––drive=1 ––format=ibm.720 [DISKNAME].hfe

When I image the disk as an scp using the same instruction (excepting the extension), this appears to work fine, but when I rewrite the disk it isn't readable anymore. Unless I also include the --raw switch, in which case it works exactly as expected.

The questions:

1. I was curious as to why I didn't need to do anything special for the hfe file, and why the --raw switch was necessary.
   1.5) If the hfe file works, is there any further benefit to the scp file?

2. If I've saved disks I no longer have access to as an scp file without using the --raw switch when it was apparently necessary, is there any hope for recovering those files?

I'm attempting to do a write-up on it. People love these pianos and their disks, and these floppies are now antiquated technology, and becoming moreso!

Thank you!

[keirf]

gw read ––drive=1 ––format=ibm.720 [DISKNAME].hfe will re-generate track data according to the known IBM 720k layout, and write that to the HFE image file. Actually it is therefore no better that writing to an img file.

I'm not sure why reading into an scp file behaves differently. It should write back to disk with about the same reliability as the hfe file. What exactly is your gw write command line?

If you really do want a raw preservation dump of your disks, then --raw is a good idea for that, and save as scp or Kryoflux raw stream files. If you just want to get the logical sector data, and are confident there is no copy protection below the logical sector/block level, then img should be fine.

If you want to share a raw scp image file I will also take a look for anything funny.