Digital Linear Tape: The New Media for Small & Medium Sized Storage Solutions

When small to medium-sized users need more storage capacity and faster backups than they can achieve with 8mm or DDS backups, there are two new formats to choose from.

Digital Linear Tape (DLT) systems have been available since 1985, but recent increases in both speed and capacity have given the technology a new lease on life. In fact, for small to medium-sized systems they have been the leading technology for the last several years. DDS or DAT tapes were the only competitors for DLT in that market, but the tape heads had a tendency to ‘drift’ which meant technicians had to monitor them to ensure storage. DLT reliability is based on a ’straight up and down’ recording mode.

Earlier this year, the introduction of Super DLT brought a tremendous boost in performance. Super DLT can store as much as 110 gigabytes on one cartridge, at a speed of 10 megabytes per second. With the speed of backup doubled, and capacity more than doubled, the technology can now reach ‘up’ to systems and networks that DLT previously couldn’t handle.

Competing technologies can offer very fast backups, but the tapes themselves contain very little data - hundreds of megabytes as opposed to hundreds of gigabytes that DLT offers.

Another technology has recently emerged that is comparable to DLT. That is LTO or Linear Tape Open, a consortium product from Seagate, IBM and Hewlett-Packard. LTO can put 100 gigabytes on a cartridge at up to 15 megabytes per second.

For cautious system administrators who don’t wish to try LTO, one technician said DLT is a more than acceptable choice: “Thirty million cartridges and a million tape drives can’t be wrong.”

Of course, Super DLT incorporates a good deal of new technology as well, so even though LTO is completely new technology, it “has a nice road map in front of it.” Super DLT uses a new recording format, but it does maintain a limited form of backwards compatibility with previous iterations of DLT. It incorporates the ability to read older tapes, although it cannot write to them, which means it would probably be most useful in allowing organizations to maintain their present archives in a useable form. Where users have thousands of tapes in their libraries, there can be a considerable saving in time and money if older tapes don’t have to be re-recorded on to newer ones. For those users who are moving from 8mm or DDS format systems, and committed to re-recording all their data, then there may be little to choose between LTO and Super DLT systems.

Today’s demands for storage capacity are increasing, and if anything there is going to be more pressure on our ability to back up, store, protect and retrieve data. Low to medium size users now have a choice: Super DLT, based on generations of iterative development and refinement, or LTO, new technology from a high-powered and stable group of technology companies.

Present archives in a useable form. Where users have thousands of tapes in their libraries, there can be a considerable saving in time and money if older tapes don’t have to be re-recorded on to newer ones. For those users who are moving from 8mm or DDS format systems, and committed to re-recording all their data, then there may be little to choose between LTO and Super DLT systems.