What Does LTO Have That DLT Doesnt?

It won't be long before we see LTO and SDLT running neck and neck for the top position.

When I first wrote about the LTO format—developed jointly last year by Hewlett-Packard, IBM and Seagate—I was impressed with the Linear Tape Open Ultrium specifications but was skeptical about LTOs ability to penetrate the tape backup market because Quantums DLT was the standard tape media at the time.

However, the consortium recently announced shipment of the millionth Ultrium media tape system—within the first year of the products availability—and boasted that the combined storage capacity of all Ultrium products shipped (approximately 180 petabytes) is nearly equivalent to all the printed material produced globally in 1995.

That is an impressive feat, but shipping numbers dont tell the whole story. After all, there are many more DLT systems out there than there are LTO systems. DLT also has a proven track record and wide acceptance in enterprise tape backup systems.

What does LTO have that can attract IT managers to switch from DLT or SDLT? For one thing, LTO is an open tape standard. DLT/SDLT, on the other hand, is proprietary to Quantum. This means that more companies are developing drives for LTO, and IT managers will have more choices when selecting drives for tape libraries.

The first-generation LTO Ultrium tape format also has a native transfer rate of up to 20M bps. Real-world numbers are closer to about 15M bps, but this is still faster than the SDLT native transfer rate of 11M bps.

SDLT still has the edge over LTO in capacity, however, with the ability to store up to 220GB of compressed data. The LTO media has a maximum capacity of 200GB when storing data with 2:1 compression.

The bottom line: LTO still has some catching up to do, but, considering the rapid acceptance of this new tape format, it wont be long before we see LTO and SDLT running neck and neck for the top position in the tape backup race.

Which tape format will you choose for data backup? Let me know at francis_ chu@ziffdavis.com.