On 1/8/2013 11:19 PM, John Ball wrote:
The drive is a known good drive and formats and boots
under MS-DOS. In order
to run it under Xenix 1.03 I need to format it again using DISKUTIL. The
controller can see the drive and seems to know it's ready but the problem is
that the utility instantly fails the entire disk the moment you start the
format.
(
http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CRW_779
0.jpg)
I only have a guess, and recent postings also discuss it. I wonder if
your lowlevel program is
attempting to read an error map from the drive and failing? There were
error maps recorded
on many drives but controllers and programs seldom bothered to try to
read them back and
just blasted the entire track when doing a low level format.
I would try to find a drive which hasn't been formatted and tested on a
system which might
have done this, and see where you get to. I know the problem existed
with SMD drives. The
manufacturers would record flaw maps on the drives and some controllers
would read and
use them. Most gracefully continued if the flaw map was not there, but
some did not.
We made a controller which overwrote the flaw maps, and used a novel
soft sector format
on the SMD drives to record, so we didn't actually need the flaw maps.
We looked at a similar
controller for the smaller drives, and it would have worked, but we
never proceeded with the
product.
I don't know if that is your problem or how to verify that. I suspect
the drive is left selected
because the controller state machine hung up for some reason, and didn't
transition back
to an idle state.
Another path to verify is whether you have the drive write protected or
enabled, and whether
the drive status as to whether it is write protected is properly brought
back to the controller.
thanks
Jim