> > At the moment all sectors are believed to be good. No sector replacement
> > is respected. All physical sectors are accessible via the MFM-controller,
> > since real c/t/s addressing is done. Access of replacement sectors instead
> > of the defect sectors has to be done via software, and this feature is not
> > implemented.
> 
> This is a problem.  I really can't run NetBSD on the VAXstation 2000
> without reliable storage.  I only have one MFM drive that has no bad
> sectors (out of 5 drives), and this one is only 20 megs.  Trying to find
> another perfect drive would be dificult.  I suppose the only way to run
> NetBSD now would be to use that drive and mount the rest over NFS or
> even totally boot off ethernet. 

Yes. As a starting point and to find out if the problem is really in 
the bad sectors you could/should try to install into these 20 megs.
For testing 10M root, 10M swap, and all the rest via nfs should 
be sufficient.

> However, the bad sector remapping shouldn't be too hard to implement.  I
> assume that NetBSD itself already has some support for sector
> remapping.  After all, bad144 is supported, right?  Adding support for
> the VAXstation 2000 bad sector remapping should be reasonably
> straightforward  after the format of the data on the drive is figured
> out.
> What needs to be done here?  I'd be willing to help out.  I don't have
> any unix kernel or VAX experience so far, but I can learn.  I have used
> C quite a lot. I'd also be willing to try figuring out data structures
> if necessary.

My problem(?) when I was fiddling with the MFM-controller was that
my disk didn't have any bad spots. Thus I couldn't check/implement
anything related to bad sector replacement.

OTOH i tried to include/prepare all the neccessary things, thus 
some of the neccessary command/flags/struct is already defined
in hdc9224.h and hdc9224.c respectively.

Ciao,
	bertram