Re: Need an 8280 formatted 8" disk

Thanks Ethan, I have no other 8" drives other than this one, and only 2 
disks of unknown status.

Yes, I've considered writing such a program to step the drive etc, but 
as the ROM of the 8280 is not documented and is AFAIK, unique in using a 
WD FD1797B-02 controller, I simply don't know how without a large amount 
of effort to disassemble the ROMS.

Rob

On 13/02/2017 15:08, Ethan Dicks wrote:
> On Mon, Feb 13, 2017 at 7:54 AM, Rob Clarke <crock@clarke-family.org.uk> wrote:
>> I'm desperately in need of a known good 8" floppy formatted on an 8280.
> An 8280?  Nice.  That's one of those devices I've wanted to fiddle
> with for the fun of it (but wouldn't want to have as my primary
> storage device).
>
>> After 18 months of occasional work, I now have my 8280 up and running, or at
>> least I think I do. DOS board is up and running, the drives are refurbished
>> and behaving, and I have a good power source. I can trace signals all the
>> way from the FDC to the read/write heads and back again.
> Sounds great.
>
>> Nevertheless, using the 2 no-name 8" disks I have, the format fails with an
>> error 21 on track 0, sector 1 every time. So, to track the fault down it
>> would really help to have a good disk. Either I can post one of my disks to
>> someone or, if you hace a spare 8" disk, I'd gladly compensate for that and
>> time, postage etc...
> I do not have any 8280-formatted media (or a drive), but... I read
> that the drive supports two formats: native ~500K GCR and standard
> 250K MFM "IBM 3740" format.  If you have a working 8" drive on some
> other platform, or even just have any DEC RX01 media, you might be
> able to start out reading blocks into drive RAM and pulling bytes out
> with M-R, as a test of non-write portions of the drive.
>
> I'd also consider writing some BASIC code to try to read different
> tracks to make sure the heads dance appropriately.  Without good
> media, of course the actual reads will fail, but the positioner should
> do the right thing.
>
> In case there is a problem with the heads, is the drive mech of a type
> that can be tested on another platform?  (Tandon TM848, for example,
> which the photo resembles)
>
> If someone can send you an 8280-formatted disk, that's great (not sure
> how many of those are out there), but I think there are some partial
> tests you can do with more common media.
>
> -ethan
>
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