> Firstly, are there restrictions on where you're allowed to put 
> partitions? If you define partitions (using sunos format) with a
> starting at cyl 0 and then dd the miniroot into it, the PROM refuses
> to boot that partition. Also, I seem to have managed to trash the
> drive's defect map at some point [is this as serious as it sounds?]

If I would be in your place, I would make a copy of the SunOS you have
from xd0 to xd1 and boot SunOS from xd1. Then you can use the SunOS
format program. Run the analyze "refresh" or "test" options on xd0.
This will give you a reasonable checked disk with bad blocks remapped.
The procedure might not find all bad blocks, but I suppose that your
disks have come to some age anyway.

I leave the miniroot questions to the ones who know.

> While I'm here, two quick queries. I also have a CDC Sabre SMD drive,
> but I can't work out how to configure it to be SMD disk 1 so it's not
> a lot of use [the DIP switches labelled 'disk ID' seem to have no effect].
> Anybody know how to do this?

If I remember right I tinkered with 2 CDCs 2 years ago and gave up just
because of the zillions of DIPS which I couldn'd get right for the Sun./

> Finally, I have a half inch magtape drive on a Xylogics xt interface.
> It's not on the 'supported hardware' list; is anybody working on
> support for it at all? 

Yes, the Stacken Computer Club owns one like that, too; no, we're not
working on a driver; yes, there was a bug in the 4.1.3 driver and yes
it now runs (and probably will continue to run) a 4.1.3 kernel with a
4.1.2 xt driver.

Harald.