Re: GS/OS won't recognize a ProDOS 8 3.5 inch disk

[Andy McFadden <fadden@fadden.com>]

Andy McFadden <fadden@fadden.com> wrote:
>>     I could create a '.SDK' archive of it and send it to you, if you
>> wish.
> 
> By all means... I'm curious to see if there's anything really odd about
> the disk.

Block 2, the first block of the volume directory, starts off like this:

000: 00 00 03 00 f5 46 4f 43 55 53 00 00 00 00 00 00  ....uFOCUS......
010: 00 00 00 00 00 00 00 00 00 00 00 00 16 d1 2b 04  .............Q+.
020: 23 01 c3 27 0d 06 00 06 00 40 06 d9 46 44 4f 53  #.C'.....@.YFDOS
030: 2e 56 31 2e 30 00 00 00 00 00 00 0f 07 00 01 00  .V1.0...........

Bytes $20 and $21 are VERSION and MIN_VERSION in the volume directory
header.  In this case you have version 35 with a minimum version of 1.

Apparently GS/OS looks at the disk, sees that a minimum version of 1
is required to read it, and concludes that it's not equal to the task.
If you sector-edit block 2 (e.g. with the Copy II+ 3.5" bit copier)
and change byte $21 to 00, the disk is treated normally by GS/OS.

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