LTO Consortium Spins Ultrium 4 Tape Format with Native Encryption
January 15, 2007 Timothy Prickett Morgan
The companies behind the Ultrium Linear Tape Out (LTO) tape drive and tape cartridge specification announced last week that the specification for the LTO 4 tape format had been completed and was available for licensing by interested parties. That means that tape drives and cartridges based on the LTO 4 format, which has integrated data encryption capability, should start appearing this year.
This time around, IBM, Hewlett-Packard, and Quantum are driving the technology behind the LTO spec; disk maker Seagate Technology partnered with IBM and HP to drive earlier generations of LTO technology.
With the LTO 4 specification, WORM capabilities, which appeared first in the LTO 3 spec, will be improved. WORM capabilities are important for companies that have to wrestle with compliance issues, since they need a data storage medium that is both inexpensive to cover their huge volumes of data as well as unalterable so the auditors don’t go crazy. The LTO 4 spec adds data encryption, but there is a catch: Only LTO 4 drives will be able to read LTO 4 cartridges with the encryption turned on. Up until now, the LTO spec had offered backward compatibility, with a given LTO tape drive being able to read cartridges back two generations and being able to write data back on the tape in a format that was compatible with the prior generation. If customers want to ignore the data encryption feature, they can however write in LTO 3 format and read in LTO 2 and LTO 3 format with the LTO 4 devices.
The LTO 4 drives have a compressed data transfer rate (assuming a 2:1 data compression ratio) that will be boosted by 50 percent to 240 MB/sec (up from 160 MB/sec with LTO 3 drives), and native cartridge capacity with compression will be boosted to 1.6 TB (double that of LTO 3 drives).
It has taken the LTO partners about two years to get each new LTO spec together. That should have meant that the LTO 4 spec should have been done in late 2004, but it was delayed until the end of 2006 in a revised roadmap. In 2005, the LTO partners scaled back on data transfer rates on future designs, cutting back from a doubling transfer rates every two years to simply boosting them by 50 percent. The original LTO drives from six years ago held 200 GB of compressed data and transferred data at 40 MB/sec. With the LTO 5 spec, tape cartridge capacity will double to 3.2 TB and data transfer rates on compressed data will hit 360 MB/sec. LTO 6 technology will double capacity again to 6.4 TB per cartridge and boost data transfer rates to 540 MB/sec.
Back in October, the LTO collaborators said that since September 2000, when the first LTO drives became available for purchase, the dozens of companies making and hundreds of companies distributing LTO products had shipped over 1.5 million LTO Ultrium tape drives and over 50 million cartridges. At the time, units meeting the LTO 3 specification, which added write one, read many (WORM) times capabilities to the tapes, had just begun shipping and the consortium members were promising that they would bring native data encryption to the LTO spec.