On Friday 06 September 2002 04:43, Brian Jonnes wrote:
>Hi all,
>
>Perhaps this is not quite the place for this question, but I hope
> it won't offend anyone ;)
>
>I will be looking to get a new tape drive, but am not very
> familiar with the current technology. I have heard of DDS, DAT
> and have used Travan. As far as I'm concerned, the Travan is out
> of the question, 'cause the tapes are so expensive (and
> apparently they are now obsolete?).
>
>So; what are the opinions of this list? (<BEGIN FLAME>...?)
In most cases, the terms DDS and DAT mean essentially the same
thing, as in a small cassette used in a helical track technology
drive, a smaller version of your home vcr mechanism. Such DDS#
numbers as you see indicate the density ability of the formulation,
with DDS4 being the current top of the line, and holding (IIRC)
20gb uncompressed.
Here at home, I use DDS2, which puts 4gb uncompressed on a 120 meter
tape, in a changer mechanism that holds 4 tapes. This, backing up
50 some gigs, using software compression where it does some good,
seems to be averaging about 60% useage per tape, so I have a little
room for expansion yet.
IMO, the driving force behind the DAT/DDS style is the relative
price of the tapes. A 10 pack of 120 meter DDS2's, from some ebay
dealer, will generaly cost you around 50 USD including the
rediculous shipping some tag on.
The service life of the tape is something I can't testify to yet, I
put 20 tapes into a 7 day dumpcycle about a year ago, in a then
brand new Seagate/Compaq 4586np drive and they are still in service
with no failures. I've had to hand cycle the cleaning tape in the
4th slot into use maybe 4 times in this same time frame.
IMO its a decent method for the home user just because its an
affordable format, and with all the other formats either not having
enough capacity, or costing 50+ USD per tape, its the only format
on the radar screen.
Would I attempt to do a commercial business with it? Today, a
strong yes given a robot changer with enough slots, no for single
tape only decks as they just wouldn't have the capacity. But for
the small business with say 5-10 major machines to backup, a
dedicated software raid server with a rack of big drives, running
rsync, also has a cost and speed advantage. I know of one such
setup with a capacity of 320 gigs in 4 160 gig drives that does its
nightly thing in lots less time than tape could since its on a
100baseT and can r/w at 50+megs a second. Built inhouse, it cost
about 1600 USD at the time. Is it as dependable as tape? Time will
tell. Can you take it offsite? In a sense, yes, by cycling enough
drives thru each slot in the array and letting the raid rebuild
itself while that removed drive goes offsite to join 3 others on a
regular rotation schedule. Its not being at this site (yet).
--
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz 512M
99.14% setiathome rank, not too shabby for a WV hillbilly
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