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