Booting Standalone Backup tape from TZ88

[Dan Mellem]

Bob Blunt:

Thank you very much for your reply.

> Do you or does your system have an available CD drive?  I just found a distro CD for V7.1 that booted right into S/A.

No, unfortunately. However, I may be able to borrow an old Apple CD drive that was similiar to our old (dead) DEC CD drive. A coworker said he may still have one in a closet somewhere. I couldn't find newer original media (only 5.5.2H4) but found possible ISOs online for 6.2 and 7. If I can get to the point of booting 7.1 off of CD, could I create a SAB tape from there or would I need to install it?

Steven Schweda:

> Having heard nothing for a while, I assumed that he'd given up.

I'm still here. :) I just got hammered with a lot of projects recently and important but invisible things like being able to restore a backup tend to slip behind the more visible requests.

It does seem odd that the CDRW drives flaked but the old caddy-load drive worked. I guess I'll need to play musical drives for that as well if I can find some. I'm guessing a new drives with adapters may not be the best choice, then.

[Steven Schweda]

> [...] If I can get to the point of booting 7.1 off of CD, could I
> create a SAB tape from there or would I need to install it?

   If you can boot into SAB, then you can run SAB.  Booting into the
read-only-VMS environment is nice for some things, but apparently not
for creating a SAB kit.  Looking at a V7.3 (official Hobbyist) disc (in
clever mode):

$$$ dire DKA600:[000000...]stabackit
%DIRECT-W-NOFILES, no files found

   Even if you had STABACKIT.COM, it would probably want to write stuff
to SYS$UPDATE, or some other place on the read-only system disk, so I'd
guess that it'd be doomed, and that's why it wasn't included in the
read-only-VMS kit.

   Given a free (read+write SCSI) disk, you could use the CD to install
real VMS onto that disk, and that'd give you a real VMS system disk,
with STABACKIT.COM, and everything else.  At that point, however, the
value of a SAB tape would fall again, because you'd now have a
better+faster real VMS system disk which could be used instead of SAB.

   On the bright side, that saves me the effort of trying to get a
big-50-narrow CD-ROM drive and a mini-68-wide tape drive onto the same
bus with a short enough cable to let them work.  (I tried with the stuff
at hand, but couldn't boot from the CD (hung) with the tape drive and
another couple of meters of cable and adapters attached.)

> It does seem odd that the CDRW drives flaked but the old caddy-load
> drive worked.

   Read+write drives are more complicated, and many things are possible.
Expecting old VAX HW/FW/SW to deal correctly with a drive which is newer
than the old VAX might be a little over-optimistic.  (Kind of you to
reserve "old" for a proper subset of that drive collection.)

> [...] I may be able to borrow an old Apple CD drive [...]

   With any unsupported drive, you might need to worry about block
sizes.  VAX and/or VMS may expect 512-byte blocks, and may or may not
tell the drive that, and the drive might not care if it's told.  On that
Toshiba drive, there are some very-low-budget cut+solder pseudo-jumpers
to select such characteristics:
      http://antinode.info/dec/toshiba_cd-rom.html

   I'm too lazy to open the box, but I'd bet a small sum that that
TXM3401E1 drive had its block-size trace cut to make it do 512-byte
blocks.

   As it says on that Web page, the (newer+faster) XM-6201 drive worked
without needing such jumpers.  I should have one somewhere in my museum,
but it's not near the top of the pile at the moment.  In any case, there
are abundant old comp.os.vms threads related to CD-ROM drives for old
VAX and/or Alpha junk.  Many worked, a few didn't.  As usual, running
the experiment can be expected to be more reliably informative than
relying on the literature (even if I wrote it).

> [...] I'm guessing a new drives with adapters may not be the best
> choice, then.

   With my old-junk supply, I've never felt the need to try such things.
I'd expect a literature search to find reports from others who have
tried them.

   Naturally, any reports of results of your experiments would be
interesting (if not actually amusing).