[comp.os.vms] 8mm tape experiences

Azog-Thoth@cup.portal.com (William Thomas Daugustine) (03/03/91)

Hiyas all. Ive seen some recent posting here and there concerning 8mm tapes,
and/or 4mm tapes, and wanted to share my experiences with those of you who
might be interested.  

About a year ago, we purchases an Aviv 8mm tape drive, that had two drives
in one box. The thing that sold us is that we didnt need to buy a new 
controller for it. It sits between the current TU81+ and the TU controller.
To choose 8mm or TU we just need to pop a switch. The only bummer is that 
we get either 8mm or TU, not both.

Before, we used to back our bank of RA82s onto about 18 mag reels of tape,
and had operator assistance for about three hours (7 days a week). About a 
week before we got the 8mm we added a bank of four RA81s, but didnt back these
up.

After we installed the 8mm, I modified the DCL in our nightly backup 
procedures, and have it save the four RA82s to one tape, and the
four RA81s to the second tape. Using this, we almost eliminated the
weekend crew. Almost...

I normally go in on saturday morning anyways, so I popped in sats save, 
and came in on sunday and did the same. Also, we do a daily job that
requires a mag tape.

Very recently, we added two more 8mm tapes. Aviv sells a slave unit that
attaches to the master. The master can support 2 units, for a total of
6 drives all together. 

I did some more mods to the DCL and now save saturdays to the first 
(master) 8mm, and save sunday to the second (slave) 8mm. Hey! I dont
need to go in on sunday anymore!

Right now, we are about 95% unattended, and operatorless. As I said, we
run a daily job that requires a mag tape, and an operator must physically
insert tapes into the units. When I am sure that the new procedures work
right (selecting the correct drive for the correct day), I can make it 
99% unattended. The daily mag tape is just a special backup of a log file
so when (and if) we need to restore that log file, its real handy on mag
tape. On sunday, that log file gets delete. My brainfart is to save that
log file as the first save set on the first 8mm tape, so its still readily
accessable, and just before the log is deleted, backup it to another disk.
Monday morning, or anytime before next sunday, we can back that onto a mag
tape for archives. 

Now, only one special job needs an operator, but they still need to
insert the tapes (anyone got any bright ideas about that?:-)

Along the line, Ive built up a cycle of about 6 command procedures
that get run each night, each submitting the next one, and the last 
one submits the next nights cycle.

To save 8 drives, the whole procedure takes 4 hours and some odd 
minutes. The procedure gets run real late at night, when we can 
guarentee that no users are online. 

Myself, I think this is fantastic! Almost purely unattended, and
automated! approx 4gb in four hours is a damn good transfer rate, 
I would guess!

Enough of my babbling, I just wanted to share that with people who 
either already run 8mm or are considering it.    

Some minor info: the Aviv master costs approx $25k (I forget what the
actual price was), each slave costs about $14k. The Aviv 8mm take drives,
hwhen selected on 8mm will emulate TU81+, so you dont need to worry about
new device drivers, etc. 

Billy D'Augustine
Azog-Thoth@cup.portal.com