On Thu, 27 Jul 2000, Brian wrote: > I found the 8mm we use for AS/400 backups here. It's a "helical scan" > whatever that means, but my 112m tape holds 2.5/5 GB, so if I math it out > (assuming it's linear) 160m should be somwhere around 3.5-4 GB uncompressed. > Is it possible that your drive will only take a 2/4 GB tape (either by > design or by "unfortunate incident")? That's a drive thing. 112m is what the Exabyte 8500C can get 5GB onto uncompressed. Still, you're right, Bob should be able to get more than 2GB on a 160m tape. BTW, helical scan means that it's a rotating head, like in a VCR. Instead of writing the tracks longitudinally along the tape, they are written by a head that is spinning, but at an angle to the tape, creating a bunch of segments that have been arranged like "angle parking," just like a row in the parking lot. Cheers, Phil M > On Wed, 26 Jul 2000, Philip C Mendelsohn wrote: > > > On Wed, 26 Jul 2000, Bob Tanner wrote: > > > > > Running Sparc Linux with a Exabyte 8mm Tape drive using 160mXL 8mm > tapes. > > > > > > I think I am going insane, but I thought 8mm did 12/24Gb. Yet, I am able > only > > > to get around 2Gb on the tape before it gives me a write error. > > > > > > Just wanted to make sure my capacity is right on the tapes before I look > else > > > where. > > > > Depends on the drive, but that's *way* higher than what I would expect. > > > > I have an Exabyte 8500C, which is rated for 5GB uncompressed, 10GB with > > the hardware compression. (It's older, but it's a rock.) > > > > I don't recall if that was 160m tapes or not, but the difference for tape > > length is linear, so that doesn't explain it. > > > > 2GB is pretty shabby though. > > > > There are lots of annoying problems that could account for it -- bad > > tapes, dirty machines, yada, yada. I have a fair amount of insight into > > the behavior of tapes and heads which I won't burden you with now :) > > > > I don't want to start a "I swear by brand X, but brand Y > > stinks" discussion, but I have some data on error rates, bad tapes > > received, and recoverability after time that suggests that the 3M / > > Imation 8mm tapes really do outperform a couple of other brands. > > > > *I'm not claiming they beat everyone else's tape.* > > > > Nutshell: Your numbers probably aren't right, but your tape is *almost* > > certainly not doing what it's supposed to, IMHO. > > > > Cheers, > > Phil M > > > > -- > > Lottery: a tax on people who are bad at math > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org > > For additional commands, e-mail: tclug-list-help at mn-linux.org > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org > For additional commands, e-mail: tclug-list-help at mn-linux.org > > > ----------------------------------------------- > FREE! The World's Best Email Address @email.com > Reserve your name now at http://www.email.com > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org > For additional commands, e-mail: tclug-list-help at mn-linux.org > > -- Lottery: a tax on people who are bad at math --------------------------------------------------------------------- To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org For additional commands, e-mail: tclug-list-help at mn-linux.org