SUMMARY: DATs and Stackers

From: Alex Zbyslaw (Zbyslaw@europarc.xerox.com)
Date: Tue Mar 24 1992 - 18:37:49 CST


I asked if anyone had experience of using a DAT for backup, especially with
as part of a stacker. I also asked about Exabyte stackers.

No-one seemed to be using a DAT stacker of any sort. Some people had various
Exabyte stackers which worked reliably. The reason I asked about
reliability is that neither of our regular supplier want to sell Exabyte's
stacker because they've had too much trouble with it, and one wouldn't sell
a DAT stacker for the same reason. The other supplier would sell a DAT
stacker (Soltronics) but hadn't actually got one out in the field yet.

One person reported quite low gain from using a DAT with hardware data
compression. (This DAT is touted as storing up-to 8Gb, with "up-to" in small
print and "8Gb" in large print!). The person reported a mere 3Gb of data per
tape.

--Alex

Thanks to the following for replying

jayl@bit.uucp (Jay Lessert)
brian%vixen%cyrix@texsun.central.sun.com (Brian Holgate)
esch@cray.xilinx.com
birger@vest.sdata.no ( Birger Wathne)
westdr%pdc@uunet.uu.net (Dave West)
Gus Teschke <gus@patella.msis.med.umich.edu>
Chris Maio <chris@boxhill.com>

-------------------------

No info on DAT devices, but I have a IGM 8MM carousel that holds 54 tapes and has
2 Exabyte 5 Gbyte tape drives in it. It has been on line since July with no problems
(other than some initial eeprom stuff in the drives). I use it to back up ~7 Gbytes
each night with a shell script. The juke box was installed in a Solbourne multi-cpu
file server with out a hitch. I highly recommend this piece of equipment, and the
people at IGM. Let me know if you need any more info.

IGM Data AutoLoader Division
Houston, Texas USA
Sales Division
(713) 578-2500
Contact: Chris Smith

-------------------------

We are using a 6-tape Exabyte stacker and are very pleased with it. It is an
ACL model 600 that we purchased as part of a package from Apunix (I know it can
be a pain to purchase US stuff in Europe, but for what it's worth...).

The stacker is *very* simple, and fairly cheap ($6000 US for the stacker *and*
the EXB-8500 inside, $2000 if you provide your own Exabyte). It is not random
access, just single pass sequential access (eject one tape, load the next,
etc.). No device driver is needed, you just go 'mt offline' to eject one tape
and load the next.

We've feed 6 tapes through it every weekend for the last three months and no
misfeeds. Simplicity is a virtue, I guess. :-) They also make a 15-tape
version.

Apunix Computer Services
5575 Ruffin Road
Suite 110
San Diego, CA 92123 USA
1-619-495-9229, (fax)1-619-495-9230
...!ucbvax!ucsd!apunix!sales, ucsd.edu!apunix.sales

-------------------------

Sorry,

no work on DAT -

but about Exabyte stackers, We have a bunch of um - runnin w/ 8500's
    ( And they work great! )

You can John Marciano a MicroAge out here - they have a direct line
with Exabyte, they got us one of the first stackers -
MicroAge is (408) 364-2932

-------------------------

You may want to call Delta Microsystems who supports a full line of Exabyte
products with device drivers and Budtool software. (510)449-6881. They
also have DAT drives and drivers.

-------------------------

Box Hill Systems sells both 4mm and 8mm stackers, including device
driver support and serial options for customers who'd prefer not to
install device drivers. We also provide additional software support
to allow our stackers to be used with Legato NetWorker or other backup
software.

If you'd like more information, please contact our sales department
at 800-727-3863.

Chris Maio
Box Hill Systems
chris@boxhill.com

-------------------------

Reliable capacity with compression? Not possible. You never know how
"compressable" your data are. One of our customers uses HP's DAT, and is
unable to reliably get more than 3Gb onto the tape. I don't know what
kind of tape he uses, but his data are fairly normal things (Source code,
executables, home directorieas, and some atmospherical data)....

Exabytes with compression should be the same. Capacity will vary according
to the data being dumped.

Physical reliability seems ok though.

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