csg@pyramid.pyramid.com (Carl S. Gutekunst) (09/19/88)
In article <459@Terra.cc.brunel.ac.uk> linda@cc.brunel.ac.uk (Linda Birmingham) writes: >Has anyone used the S159 8mm Cartridge Tape subsystem on Pyramids ? I don't know what people in the field have been doing, but here we've been experimenting with them in the lab. (Not me -- someone else. So everything I am writing here is hearsay, third hand, twice removed.) For those who aren't familiar with the technology, these are 2 GByte digital tape drives, using conventional 8mm video tape. I forget who we bought ours from, but all the drives are made by Sony so it makes little difference who the intermediate vendor is. While these drives are interesting, they are hardly a panacea. The big problem is reliability. The drives are rated at "10,000 hours, 10% duty cycle," which means that to achieve a 10,000 hour life you cannot use the drive more than 2 hours and 2 minutes per day. That's a little more than a gigabyte per day. If you have more than that, the drive will wear out sooner. Sure enough, when we ran the drives continuously, they died consistently in about two months. Probably to most important factor, though, is that Sony is telling systems manufacturers to wait for digital DAT drives. These will be "only" 1.2 GB per tape, but will be industrial quality and a lot faster. <csg>
csg@pyramid.pyramid.com (Carl S. Gutekunst) (09/20/88)
In article <40260@pyramid.pyramid.com> I wrote: >... Sony is telling systems manufacturers to wait for digital DAT drives. >These will be "only" 1.2 GB per tape, but will be industrial quality and a >lot faster. I was corrected: the Sony DAT drive is *slower* than the 8mm drive. Per-tape time is about the same, but the DAT has half the capacity. Incidentally, 3M has been making a strong marketing pitch for their latest 1/4" cartridge offering. These will store something like 600 Meg per tape. I don't know about speed, although traditionally they have run about 30 minutes for a 600' tape. <csg>
decouty@irisa.UUCP (Bertrand Decouty) (09/21/88)
In article <40260@pyramid.pyramid.com> csg@pyramid.pyramid.com (Carl S. Gutekunst) writes: [ text deleted] >While these drives are interesting, they are hardly a panacea. The big problem >is reliability. The drives are rated at "10,000 hours, 10% duty cycle," which ^^^^^^^^^^^ >means that to achieve a 10,000 hour life you cannot use the drive more than 2 >hours and 2 minutes per day. That's a little more than a gigabyte per day. If >you have more than that, the drive will wear out sooner. Sure enough, when we >ran the drives continuously, they died consistently in about two months. ^^^^^^^^^^^^ > ><csg> Could you be more precise, please? Is it 10% continuously or not? Because doing a back-up of 500 MBytes of a local disk on a Sun 3 can take as long as 1 hour but the same back-up of a *remote* disk take 3 times more! Which method is the best for big back-up (near a full tape, 1.7 GB for a 90mn tape): 3 hours continuously or 3 times 1 hour separated by 1 idle hour? (it is an example). Is there any people having such an experience of large and long back-up? It seems to me that many people are interested by Exabyte-like products but few people really uses it for more than 500 MB back-up, so we have no idea of real reliability: dump failure, hardware failure... Thanks for any info. ----- Bertrand DECOUTY @ INRIA-IRISA (Centre de Rennes) ----- +------------------------------+----------------------------------------------+ | IRISA - INRIA | EMAIL : decouty@irisa.fr | | Campus de Beaulieu | UUCP : {mcvax,inria!}irisa!decouty | | F-35042 Rennes Cedex | decouty@irisa.UUCP | | FRANCE | BITNET: DECOUTY@FRCICB71 | +--------------------------+---+--------------------+-------------------------+ | PHONE : +33 99 36 20 00 | TELEX : 950473 UNIRISA | FAX : +33 99 38 38 32 | +--------------------------+------------------------+-------------------------+