Path: utzoo!attcan!uunet!midway!chsun1!kusumoto From: kusumoto@chsun1.uchicago.edu (Bob Kusumoto) Newsgroups: comp.periphs.scsi Subject: Re: DAT versus 8mm Tape Message-ID: Date: 5 Nov 90 22:38:07 GMT References: <272DB1E1.9737@orion.oac.uci.edu> Sender: news@midway.uchicago.edu (News Administrator) Organization: University of Chicago Lines: 59 sfrank@orion.oac.uci.edu (Steven Frank) writes: >I need to buy a backup system in the 1-2 GB range for UNIX. I am >comparing DAT and Exabyte 8mm tape. >1. Any opinions on the merits and problems with each system > would be welcome. 8mm: double storage capacity of the DAT, with the media capable of handling at least 5GB if not more without compression. Slower than DAT for file recovery, costs more (exabyte is the only company that makes 8mm drives). Cheap tapes (commerical Sony 8mm tapes can run between $5 and $10, exabyte certified tapes run between $10 and $15). DAT: current storage capacity around 1.3GB and the media is pretty close to its capacity, but it's possible to expand it with compression (but then you get into the pros and cons of compression and data reliability). Tapes costs around $12, with the range betwenn $10 and $17. Recovery of a file is faster since it can reach the file more quickly than 8mm. Lots of companies sell DAT drives because the technology is connected to commerical audio markets (cost of R&D is lower on DAT than 8mm). >2. Can anyone suggest articles of intermediate technical level that > describe how DAT and 8mm tape systems work and what the pratical > details are of using these systems (eg, seek times, etc) The recent SunTech Journal I got (sept/oct) has a few articles talking about the ins and outs of 8mm and DAT technology. >3. What is the cost for medium for DAT drives? pricing for DAT drives is around $4k-$6k. Exabyte drives go for $6k-$7k although I've seen some people try and sell them for $9k and up. The question is what's important for you: storage capacity: 8mm wins hands down. The new exabyte 8500 holds 5GB of storage on an single 8mm tape (doubles the current throughput of the 8200 as well). fast recovery: DAT wins here. I think the commercial audio DAT tapes can go from one end to the other end of the tape in 38 seconds. Imagine how fast it can locate a file on a tape for you compared to a few minutes on the Exabyte. cost: the DAT drive costs less but the tapes cost more. If you look at the price of the tape per GB, the DAT tapes cost even more. Since the commerical Sony 8mm tapes are pretty cheap, and they can handle at least 2.3GB if not the newer 5GB format, they cost less per GB. Even the tapes certified to go 5GB when the 8500 is out from OEMs would be cheaper at $20 per tape per GB than DATs (at 5GB 8mm at $20 each, the cost is $4/GB, while a $10 DAT is $7.70/GB). the SunTech article also talks about the current debate and "war" over which compression technology is being used in DAT drive to increase their capacity, but you also have to weigh how much more important capacity is worth to you over data integrety after uncompression. Bob Bob Kusumoto | Find the electric messiah! Internet: kusumoto@chsun1.uchicago.edu | The AC/DC God! Bitnet: kusumoto@chsun1.uchicago.bitnet | - My Life with the Thrill Kill UUCP: ...!{oddjob,gargoyle}!chsun1!kusumoto | Kult, "Kooler than Jesus"