On Wed, 28 Jan 1998, Michael Sokolov wrote:

>    Anders Magnusson <ragge@ludd.luth.se> wrote:
> > Actually, the RD disk shouldn't use BAD144 but another way of bad block
> > forwarding; the same as RA disks use. In that case a RD disk from a
> > MV2000 can be put directly into a MVII with RQDX3, otherwise it won't
> > work if there are bad blocks on it.
>    I'm assuming that by "RA disks" you have really meant MSCP, right? (It's
> very unfortunate that in all VAX Unices that I have seen MSCP disks are
> called ra...)

Yes, he meant MSCP.

> But I have thought that MSCP disks use bad144, don't they?

No. What made you think that?

> And who does the bad block forwarding in this case anyway? Is it the
> intelligent MSCP controller or the OS?

Both. Neither. It depends on which controller. The one in the MV2000 seems
to do nothing, so the OS does everything.
In the UDA50 (and KDA50) when a bad block occurs, the OS needs to revector
the block, but after that, the controller automatically gets the
revectored block instead, without the OS knowing. I'm not sure where the
RQDX3 stands. In the HSCx0, the controller does it all for you, I think.

	Johnny

Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt@update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol