At 10:15 AM 12/20/2000 -0500, NetBSD Bob wrote:
>Ahhh, so if I am interpreting you correctly, I can merely set the ID of
>the RRD42 to 4 (where it usually is) and hang it off my Dilog SCSI card?
>Gee, if that is the case, that is quite fortunate.

That's correct. I've booted my MV2 from an Emulex UC07 this way. One caveat 
on the Emulex was that I had to go into its firmware (connected through the 
console) and tell it that the disk at target 5 was a removable disk and to 
allow it to eject. Before I did that once the system powered up the drive 
wouldn't let me get disks out of it! FWIW I was using an older 3rd party 
Sun compatible drive.

>I was thinking it
>required a special cdrom card on the Qbus.

The RRD40 (and RRD50) both required a special interface card (and in the 
case of the former a really weird disk caddy!)

>As to scsi tapes like the Cipher 9 track decks with single-ended scsi,
>why or why not could they also not be hung off the disk scsi bus?

The SCSI card is actually emulating a DEC protocol called MSCP, tapes used 
a protocol called TMSCP. Depending on the card, they could emulate one or 
both of those protocols. For example on the CMD cards you can have disks 
and tapes on the same SCSI "string" and the card will emulate one protocol 
or the other as needed. On the Emulex card everything on one string was 
*either* tape *or* disk. That is why the UC08 (which is really just a dual 
UC07) was fairly popular since one side would be the "tape" controller and 
the other side would be the "disk" controller.

>The Dilog card has 7 ID's it can handle, if memory is correct.
>I was thinking scsi tape decks on Qbus also required special tape
>adapters.  If not, again, that would be quite fortunate.

Remember, its TMSCP adapters. That is why Viking called their SCSI cards 
QTO (Q-Bus Tape Only), QDO (Q-Bus Disk Only) and QTD (Q-Bus Tape and Disk). 
The adapter has to "appear" in Q-bus memory space at two different places 
for tapes and disks so that required slightly more sophisticated firmware.

>Would that also suggest I could stick an Exabyte 8200/8500 tape or a
>9/18 track 1/4 inch streamer tape like an Archive or Wangtek transport,
>on the Dilog card, too?

Again, only if your Dilog can do TMSCP support, if it can then yes you can 
use those tapes. My 4000/300 with the Emulex card has an Exabyte 8200 as 
its MUB0: tape drive and it can boot from it just fine.

However, all of this discussion becomes moot on the non-Q-Bus series of 
VAXen (3100, 4000/60, 4000/90, VLC, etc) because those VAXen talk to the 
SCSI bus directly through the NCR chips.

>This is getting informative?

This is a question?

--Chuck