30 Nov
2019
30 Nov
'19
5:17 p.m.
On 11/30/19 7:16 PM, Fred Cisin via cctalk wrote:
On Sat, 30 Nov 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.
bill
I'll start with the simple and funny one.? If
i run FORMAT
it formats all 80 tracks.? :-)? Seems like the definition
for an 8" disk as selected in the config menu is just plain
wrong.? Of course, once it formats all 80 :-) tracks any
attempt to access it, like a DIR, just returns "sector not
found".
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
it did format; it sees sectors, but not the one that you asked for.
That may be that the format command setup and the read are in
disagreement on sector numbers, and/or sector size.
It could also happen if it ended up on the wrong track.? (then the C
field of the CHRN of the sector doesn't match the C field of the CHRN
requested)
Even a non-functional stepper could do that.? Be well aware thet
"VERIFY" checks whether there are READABLE sectors, not whether they
have correct content.? If you want RELIABLE code, include a READ after
WRITE, rather than rely on the FDC "VERIFY".
A non-functional WRITE (including FORMAT) will VERIFY just fine, but
leave behind whatever had been on the track before, rather than what you
though that you had put there.
PC FDC returns error code 2 for not seeing address mark.? However,
MS-DOS goes through a short list of codes that it knows, and then falls
through to "error, but none of the above" and says "General Failure"
(I
can't help but think that that was one of the brass in VietNam)