Linear Tape-Open

Linear Tape-Open (or LTO) is a magnetic tape data storage technology originally developed in the late 1990s as an open standards alternative to the proprietary magnetic tape formats that were available at the time. Seagate, Hewlett-Packard, and IBM initiated the LTO Consortium, which directs development and manages licensing and certification of media and mechanism manufacturers. The standard form-factor of LTO technology goes by the name "Ultrium", the original version of which was released in 2000 and could hold 100 GB of data in a single cartridge. The most recent version was released in 2007 and can hold 800 GB in the same size cartridge. Since 2002, LTO has been the best selling "super tape" format and is widely used with small and large computer systems, especially for backup. Its popularity can be attributed to both the innovative technology developed as well as the attractive pricing that is the result of the competitive market made possible by an open standard.

Historical context

Half-inch (1/2") magnetic tape has been used for data storage for more than 50 years. In the mid 1980s, IBM and DEC put this kind of tape into a single reel, enclosed cartridge. IBM called their cartridge 3480 and DEC originally called theirs CompacTape, but later it was renamed DLT and sold to Quantum. In the late 1990s, Quantum's DLT and Sony's Advanced Intelligent Tape (AIT) were the leading options for high-capacity, high speed tape storage for PC servers and UNIX systems. Those technologies were and still are tightly controlled by their owners. Consequently, their availability was fairly limited and prices were relatively high.

IBM, HP and Seagate sought to counter this by introducing a more open format. [ cite press release |url=http://www.ultrium.com/newsite/html/news_11_04_97.html |title=HP, IBM, And SEAGATE Agree To Establish Open Format Specifications For Enterprise And Network Storage |publisher=LTO |date=November 4, 1997 |accessdate=2007-10-15] Much of the technology is an extension of the work done by IBM at its Tucson lab during the previous 20 years. [ [http://www-03.ibm.com/ibm/history/exhibits/storage/storage_fifty.html IBM storage history] ]

Around the time of the release of LTO-1, Seagate's magnetic tape division was spun off as Seagate Removable Storage Systems, later renamed Certance which, soon after, was acquired by Quantum Corp.

Form factors

LTO technology was designed to come in two form factors, Ultrium and Accelis. As of 2008, LTO Ultrium is very popular and there are no commercially available LTO Accelis drives or media. In common usage, LTO generally refers only to the Ultrium form factor.

Accelis

Accelis was developed in 1997 for fast access to data by using a two-reel cartridge that loads at the midpoint of the 8 mm wide tape to minimize access time. IBM's (short-lived) 3570 Magstar MP product pioneered this concept. The real-world performance never exceeded that of the Ultrium tape format, so there was never a demand for Accelis and no drives or media were commercially produced.

Ultrium

LTO Ultrium was developed as a (more or less) drop-in replacement for DLT and has a similar design of 1/2" wide tape in a (slightly smaller) single reel cartridge. This made it easy for robotic tape library vendors to convert their DLT libraries into LTO libraries.

An Ultrium cartridge's dimensions are 102.0 x 105.4 x 21.5 (mm).

* An Ultrium drive is expected to read data from a cartridge in its own generation and at least the two prior generations.
* An Ultrium drive is expected to write data to a cartridge in its own generation and to a cartridge from the immediate prior generation in the prior generation format.

Generations

References

External links

* [http://www.redbooks.ibm.com/abstracts/sg245946.html IBM's LTO Redbook] – IBM System Storage Tape Library Guide for Open Systems
* [http://www.lto-technology.com/newsite/index.html Linear Tape Open] – Consortium Homepage
* www.tandbergdatacorp.com/support/LTO1_2TapeUsersGuideFeb2.pdf Tandberg drive manual with lots of generic details (link inactive as of 2008-05-18)
* [http://www.tdk-media.com/professional/support/pdf/TDK-6pg-LTO3-Full.pdf TDK brochure with a diagram of tape and cartridge construction]
* [http://www.ecma-international.org/publications/standards/ecma-319.htm ECMA 319] – [http://www.ecma-international.org/publications/files/ecma-st/ECMA-319.pdf Specification of Ultrium 1]
* [http://www-1.ibm.com/support/docview.wss?rs=543&context=STCVQ6R&q1=ssg1*&uid=ssg1S7000429&loc=en_US&cs=utf-8&lang=en+en IBM LTO Ultrium Cartridge Label Specification, Revision 3]
* [http://tapelabels.librelogiciel.com An online generator for LTO barcode labels]

ee also

* Magnetic tape
* Tape drive
* Tape library
* Data compression