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
