The current P112 is a reissue from years ago, right? I remember I had one ? and I may
still have it somewhere ? but I only used it with 3.5? drives. Somehow I think it was
built that way by design (the board outline fit on a drive).
I don?t know how available the code is, but I would look at the firmware on the board. To
me it sounds like it has a bad drive definition. The 8272 is pretty easy to program for (I
use it on my IMSAI).
As an aside, I use a modified YD-380 (5.25? HD) drive to replace the 8? drives on my IMSAI
so as a quick test you could use one of those. At least it can step to 80 tracks and has
the same speed and bit rate. I have instructions on my site how to use it.
Rich
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On Sat, Nov 30, 2019 at 8:42 PM -0500, "Bill Gunshannon via cctalk" <cctalk
at classiccmp.org> wrote:
On 11/30/19 8:28 PM, Fred Cisin via cctalk wrote:
> 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.
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.
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