Problems Dumping Humble Indie Bundle 12 Floppy Disk

[ghalfacree]

A few bundles ago, Humble Bundle launched a physical reward set which included a 'shareware' floppy disk. It arrived today, and I dumped it via the KryoFlux for posterity - or I tried to. It didn't work, however: dumping to preservation stream format appeared to function correctly but with occasional retries due to "buffering error", but then turning that into an MFM disk image results in a 20MB file containing what appears to be some or all of the real data interspersed with zeros with all sectors reporting "Unknown" rather than "OK" and with a single bad sector at the end.

Dumping at the command line with "dtc -ftest -i0 -i2 -d0 -ftest.img -z2 -i4" gives the following log output:

Code: Select all

00.0    : frev: 79457, drift: 0.591 us, tfer: 380147 B/s, rpm: 300.135
00.0    : band: 1.996 us, 3.011 us, 4.012 us
00.0    : base: 1.004 us [99.702%], band: 1.996 us, 3.011 us, 4.012 us
00.0    : MFM: <error>, trk: 000, sec: 255, mis: 236, *H +8
00.1    : frev: 93288, drift: 0.325 us, tfer: 449096 B/s, rpm: 300.138
00.1    : band: 2.006 us, 3.009 us, 4.004 us
00.1    : base: 1.003 us [99.795%], band: 2.006 us, 3.009 us, 4.004 us
00.1    : MFM: <error>, trk: 000, sec: 255, mis: 236, *H +7
01.0    : frev: 80624, drift: 1.215 us, tfer: 384987 B/s, rpm: 300.141
01.0    : band: 1.998 us, 3.010 us, 4.011 us
01.0    : base: 1.003 us [99.739%], band: 1.998 us, 3.010 us, 4.011 us
01.0    : MFM: <error>, trk: 001, sec: 255, mis: 236, *H +11
01.1    : frev: 76009, drift: 0.683 us, tfer: 356341 B/s, rpm: 300.143
01.1    : band: 1.989 us, 3.011 us, 4.014 us
01.1    : base: 1.004 us [99.597%], band: 1.989 us, 3.011 us, 4.014 us
01.1    : MFM: <error>, trk: 001, sec: 255, mis: 236, *H +4
02.0    : The streaming device reported a buffering error

That then repeats for what seems to be every sector on the disk.

The disk appears to be fine, and inserted into a standard USB floppy drive mounts fine as a FAT-formatted 1.44MB floppy.

I've uploaded a zipped copy of the preservation stream dump here, while a valid image of the disk created using a standard USB floppy can be found here.

Any guidance on where I'm going wrong would be appreciated!

[mr.vince]

You can ignore the buffering error, this is due to busy USB connection...

What's fishy is the 255 sectors per track. Have you tried enforcing the correct number, e.g. 9 or 18?

[ghalfacree]

What's fishy is the 255 sectors per track. Have you tried enforcing the correct number, e.g. 9 or 18?

Aha! Sure enough, forcing 18 sectors per track results in a usable image. It doesn't particularly *like* it - I used the GUI, and it showed every single track as being "Good+Modified", apart from a bunch at the end which were excluded from the image as having too many sectors - but it certainly worked, and as far as I can tell all the files are where they should be. Thanks for the help!

[IFW]

Modified just means in this case that the disk was not professionally duplicated.