Electrical, Duct, Scotch: The Answer Is Tape

DLT (Digital Linear Tape) Quantum's DLT is the reigning speed and capacity champion. The powerhouse DLT 7000 drive preserves 35 GB of uncompressed data per cartridge and transmits it at a scorching 5 MB per second. Add compression, and you have a theoretical 10 MB per second transfer rate with a 70-GB cartridge. Quantum is the sole manufacturer of DLT drives, and you shouldn't expect this to change anytime soon. DLT drives are the most expensive--a standalone DLT 7000 drive is about $8,000, and a piece of media will set you back another $100. While the drive itself is costly, the media's huge capacity comes in about $3 per gigabyte. So, once you've paid off the drive, DLT turns out to be less expensive than DAT. In our tests, DLT performed as pr omised. Clearly the fastest tape media, it delivered on its promises of fast restore of scattered files. DLT's speed advantage for scattered files is a direct result of its linear serpentine recording method. DLT was also the noisiest drive we tested. Its speed makes it ideal for multiple backup scenarios. It's ideal for workgroups with extremely narrow backup windows, and it is perfect for online databases that must be backed up quickly. 8-mm Tape If any technology is going to give DLT a run for its money, it's 8-mm tape. Combining high-capacity, high-speed backup with advanced tape design features, 8-mm tape comes in two flavors: Exabyte's Mammoth and Sony's Advanced Intelligent Tape (AIT). Exabyte's Mammoth stores 20/40 GB and blasts data across the bus at a very respectable 3 MB per second--6 MB per second in compressed mode. Drives sell for $4,195, which falls right between DLT and DAT. Mammoth cartridges retail for $100. Sony AIT's claim to fame is a 16-KB m icrochip called Memory in Cassette, which holds header information--volume, system log, catalog. The chip speeds up file searches, tape initialization and error-rate data storage for archival maintenance. As a result, performance improves with restores because the tape software obtains the location of the file from the chip rather than the tape header. Our subjective tests indicated that the AIT was slightly faster than the Mammoth drive at restoring files, but not by a huge margin. Like Mammoth, AIT serves up data at 3 MB per second (uncompressed mode) and 6 MB per second (compressed mode). AIT holds more, storing 25/50 GB. The average price for an AIT drive was $4,999, with cassettes running about $100. AIT will set you back $4 per gigabyte while Mammoth comes in at $5 per gigabyte. Ultimately you pay less for the drive than DLT, but the actual backup cost (once the drive has been paid for) is $1 to $2 higher per gigabyte. Despite these minor cost differences, both 8-mm technologies are attractive to smaller workgroups that don't need the blistering speed of DLT. For starters, 8 mm is less expensive; and if you don't need DLT, why not save money? The technology is perfect for those without online databases and restore windows that aren't critically narrow. Performance is certainly good enough in either of these scenarios, and the technology is reliable. QIC (Quarter-Inch Cartridge) The latest moves on the QIC (Quarter-Inch Cartridge) front come from Tandberg Data, which has adapted the technology for its data cartridge-sized MLR (Multichannel Linear Recording) protocol. Seagate's Travan-4-based Hornet NS8 drive is less dramatic, holding 4/8 GB of data, which it transfers at 500 KB per second/1 MB per second. It sells for $400 and its media is about $40. MLR holds 16/32 GB and shoots it across the bus at 2 MB per second for uncompressed data, or 4 MB per second for compressed data. MLR retails for $1,949, and tapes sell for about $60. Only MLR is truly suited for workgroup backup. Slightly faster and larger than DAT, MLR makes sense for the same market segment as DAT: smaller workgroups without online databases or mission-critical applications that don't require extremely fast backups. Travan's performance and capacity simply isn't enough for multiple system backup. While it may make sense for individual users and SOHO networks, it simply doesn't cut it in the workgroup arena. Even in the small-scale environment, you might be better served by a high-capacity ZIP drive than a Travan drive.