30 Nov
2019
30 Nov
'19
4:16 p.m.
On Sat, 30 Nov 2019, Bill Gunshannon via cctalk wrote:
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)