1 Dec
2019
1 Dec
'19
1:41 a.m.
On 11/30/19 8:28 PM, Fred Cisin via cctalk wrote:
I was hoping there would be people here who did. I have had these
SBC's for several years but have never even powered one up before.
> 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?
I have no way of knowing. My first test was to try formatting a disk
and then reading a (blank) directory. But, as I said, while it says
the format was successful it can not read the disk.
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.
Again this is why I need to find someone with experience with the P112.
I am beginning to suspect these were not as popular in reality as they
seemed to be on mailing lists.
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!)
Well, I haven't tried 5.25" but 3.5" disks format/read/write just fine.
bill