info-vax@ucbvax.ARPA (11/11/84)
From: allegra!emory!km@BERKELEY (Ken Mandelberg)
We are about to add our third Vax. One runs VMS and the other
two will run 4.2BSD. Until now (with just two Vaxen) we handled
tape drives by just dual porting them. With 3 Vaxen the issue
is more complicated. Adding another good tape drive is expensive,
and dual porting will not handle peek needs and breakdowns
in any optimal way.
What comes to mind is some scheme for putting all the drives
on an ethernet. However, to be useful to us this must work
for both Unix and VMS. Also one vax should not expend any
resources on the others to access the drives (or for that matter
require any of the other Vaxen to be up).
I guess what I am fishing for is a tape server that talks
to all the tape drives (a variety of fancy DEC drives),
and uses the ethernet to talk to the Vaxen, together with
hardware/software on the Vaxen that make it look like the
drives are local.
Any suggestions?
(We run EUNICE on the VMS VAX, but a solution that exploits
this is not likely to be sufficiently dependable. A Unix
only solution would be better than nothing.)
Ken Mandelberg
Emory University
Dept of Math and CS
Atlanta, Ga 30322
{akgua,sb1,gatech}!emory!km USENET
km@emory CSNET
km.emory@csnet-relay ARPANETinfo-vax@ucbvax.ARPA (11/11/84)
From: medin@ucbarpa.BERKELEY (Milo Medin) Aviv makes some nice multi-port tape drives, we here at UC have a set and are very pleased. 4 ports on the controller, not only 2. But you have DEC drives, so thats probably not an option for you. I question the decision to put the drives on an ethernet, even if you could, and I seriously doubt that if you want the drives used by 4.2 and VMS. Remember, ethernet controllers sit on the unibus. Do you really want to put a 6250 drive on a 500 KB/s bus with all sorts of other things on it? I'd suggest contacting vendors of multiport Massbus controllers and seeing if they can be kludged to use the DEC drives. You think things are slow now, put them on the ethernet and you aint seen nothin' yet! Milo
info-vax@ucbvax.ARPA (11/13/84)
From: hplabs!oblio!monte@BERKELEY (Monte Pickard) Do not forget that if the drives are on the ethernet you have the cost of at least four ethernet connections (your three machines, and the server), possilbly seven. Approx. $3000-8000 cost range. The problem is not 'only' finding a tape server, or finding one that talks to both Unix and VMS, but also finding one that is cheaper than adding another tape drive. I would be interested in what solution you finally chose. Monte Pickard - Counterpoint Computers ..!ucbvax!hplabs!oblio!monte
info-vax@ucbvax.ARPA (11/15/84)
From: decvax!genrad!bolton!garry@BERKELEY (Garry Baer) Put a controller in each system and physically move the drive to each system as needed. given the controller and cables exist on each, it becomes a simple matter of management. If you a $$$ wise, this may be your least expensive way out. porting drives is a better solution IF your machines are in the same Physical area. You have many options, but need to specify the order of importance: 1) price 2) performance 3) supportability 4) DEC/non-DEC requirements/preference "Given unlimited time and money, anything can be done." Garry Baer
info-vax@ucbvax.ARPA (11/26/84)
From: dual!unisoft!kridle@BERKELEY