P112

[Fred Cisin]

>> A lot could depend on how the software is interpreting the FDC return
>> codes.
>>
>> In the case of PC BIOS (765), error code number 4) that would mean that

On Sun, 1 Dec 2019, Bill Gunshannon via cctalk wrote:
> I think you missed something.  This is a P112 SBC not a PC.  I watch
> the head step from track to track until it runs into the stop after
> passing the last real track.  I have a dbit 8" adapter and it displays
> the track count and I watch it go from 0 to 79.  I am assuming the
> problem is that wherever the disk parameters are being stored on the
> P112 they are wrong for 8" disks.

That's exactly why I said that it depended on how the software interprets 
error codes, and used PC as an eaxample for comparison, not that it would 
necessarily be the same.
You are absolutely right that I don't know anything about P112 disk 
access.

You are right that the disk parameters are obviously wrong for 8", if only 
the wrong track count.  I have seen THAT error before.
Are the OTHER parameters at least usable?

If it says "sector not found", then there is a possibility (LIKE the PC 
example that I used), that that may mean that it sees sectors, but not 
the right ones.  But, there is still the possibility that it is using 
that message for any and all disk errors.



BTW, I understand that NEC uses 77 tracks on their high density 5.25 and 
3.5 inch formats, and 360RPM for 3.5".   (Same parameters for all three 
sizes!)