david@phys.anu.edu.au (David Baldwin) (06/06/91)
I am looking at evaluating DAT and Magneto-Optical disks for archival purposes, mainly due to their good access times. Target environments are VAX/VMS and Ultrix, on SCSI based systems (3100s). At present we use 8mm, but its very slow to get a file off the end of a tape. DATs can access any point in the tape within 20 secs, and the media is cheap - has anyone heard of archival software that can take advantage of the quick search these devices offer? MO disk is a bit more expensive, but can be mounted into the filesystem, etc. It will need special drivers for Ultrix or VMS, or else some kind of adapter to make it look like a hard disk - this is necessary since ordinary hard disk drivers can't cope with removeable media. Does anyone have any experiences with these devices on VAX/DECStation 3100s? Thanks in advance, David. -- ================================================================================ = David Baldwin Internet: david@phys.anu.edu.au Head, School Computer Unit, Phone: (intl) +61+6+2490104 Research School of Physical Sciences, (Australia) (06) 249 0104 Australian National University FAX: (intl) +61+6+2491884 Canberra, ACT, Australia (Australia) (06) 249 1884 ================================================================================ =
ghg@en.ecn.purdue.edu (George Goble) (06/10/91)
In article <1991Jun6.034023.3359@newshost.anu.edu.au> david@phys.anu.edu.au writes: >I am looking at evaluating DAT and Magneto-Optical disks for archival purposes, >mainly due to their >good access times. Target environments are VAX/VMS and Ultrix, on SCSI based >systems (3100s). >At present we use 8mm, but its very slow to get a file off the end of a tape. > >DATs can access any point in the tape within 20 secs, and the media is cheap - The Exabyte 8mm "8500" can move at near DAT speeds. They also have an 8200-SX which has high speed positioning, but is more cumbersome than the 8500. The 8500 holds around 5GB on a P5-90 tape. --ghg
mah@wu-wien.ac.at (Michael Haberler) (06/11/91)
In article <1991Jun9.212006.25244@en.ecn.purdue.edu>, ghg@en.ecn.purdue.edu (George Goble) writes: |> The Exabyte 8mm "8500" can move at near DAT speeds. They also have an |> 8200-SX which has high speed positioning, but is more cumbersome than Yes, but with a really bizarre positionioning method. Do you want to write down the record number where your backup ended? I rather have a file mark. - michael -- Michael Haberler mah@wu-wien.ac.at, mah@awiwuw11.bitnet University of Economics and Business Administration A-1090 Vienna, Augasse 2-6 Biz: +43 (1) 31336 x4796 Fax: 347-555 Home: +43 (1) 961-679 (voice & fax) D-Netz: +43 (663) 811-056
sdesmara@sobeco.com (s.desmarais) (06/12/91)
In <1991Jun11.001118.10538@swdsrv.edvz.univie.ac.at> mah@wu-wien.ac.at (Michael Haberler) writes: >In article <1991Jun9.212006.25244@en.ecn.purdue.edu>, ghg@en.ecn.purdue.edu (George Goble) writes: >|> The Exabyte 8mm "8500" can move at near DAT speeds. They also have an >|> 8200-SX which has high speed positioning, but is more cumbersome than >Yes, but with a really bizarre positionioning method. Do you want to >write down the record number where your backup ended? I rather have a >file mark. >- michael Yup, good ol' file marks. That's what we're using here. We're putting file marks on the exabyte tapes every 100M. To restore from the end of a tape, we just forward space file a couple of file, and start the restore from there. Restoring from the end of an exabyte tape takes about 20 minutes. We're keeping a list of files dumped so we know in which section of the tape they are. But I'd be interested in knowing more about that "record number" scheme. -- Stephane M. Desmarais sdesmara@sobeco.com ou sdesmara@sobeco.ca Division STS - Groupe Sobeco Inc. {uunet | mcgill-vision}!sobeco.com!sdesmara 505 boul Rene-Levesque Ouest bur: (514) 878-9090 poste 297 Montreal, Quebec CANADA H2Z 1Y7 fax: (514) 875-2673 dom: (514) 733-3245