Path: utzoo!attcan!uunet!aplcen!samsung!cs.utexas.edu!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!jr3w+ From: jr3w+@andrew.cmu.edu (John Davis Raborn) Newsgroups: comp.sys.sequent Subject: Re: Exabytes on Sequent Message-ID: Date: 20 Feb 90 15:20:56 GMT References: <4389@jarthur.Claremont.EDU> Organization: University Administration, Carnegie Mellon, Pittsburgh, PA Lines: 36 In-Reply-To: <4389@jarthur.Claremont.EDU> We are using a MegaTape 8mm tape (shipped by Sequent) unit on our Symmetry 27. I love the damn thing. It's fast (relative to 9 track). We have it's controller on the multibus along with the 9 track controller. I have plans to eventually move my monthly dumps to 8mm so the two devices would be working together. I'm assuming the controllers will be "smart" enough to work together, which of course is a danagerous assumption due to speed, block size, etc. It has been suggested by Sequent that there shouldn't be a problem here. We'll see. We run automated backups at 3:00 am every weekday. The tapes hold about 2.04 gig, which is fine for us, so far. Everything has been a real plaesure. Some notes: 1. DUMP can't handle the helical scanning, so you get HDUMP with the package. It's just a modified dump, basically, the same parameters. 2. RESTORE works fine. 3. We are working with big density, ie, 3.95 bpi on the drive. 4. The only "problem "I've had has been with MT commands. I get thrown off line alot. The manuals talk about it, but i tried it any way. REWIND and FSF are ok, but BSF causes the problems. However the 8mm is fast enough that it isn't that much of a pain to REWIND and FSF instead of BSF. REWOFFL is ok too. Please realize that I use the term FAST with caution. At first my expectations were let down, but the more I use the drive , the more I love it. The drive does a lot of work. For example, it often retensions itself depending on the command, so that takes a few seconds (a minute??). Also, if EJECT is hit, I believe it retensions itself again. Davis Raborn Carnegie Mellon University Administrative Systems UCC 167 Pittsburgh, PA 15213 work: 412 268 8554