Linear Tape Open
Linear Tape-Open, LTO short, is a specification for ½ -inch magnetic tapes and the corresponding tape drives. It was developed by IBM, HP and Seagate as a community project. With the purchase of Seagate's business for magnetic tapes by Quantum Quantum LTO- alliance in the place of Seagate entered.
A special feature of LTO is that it was not planned from the start as a single vendor solution. Thus, magnetic tapes and almost all robotics manufacturers autoloaders and libraries for LTO are offered today by over 30 manufacturers. These are certified by the copyright consortium. In addition to its members only Tandberg Data also produces the tape drives.
Originally it was planned to establish the two formats LTO Ultrium and LTO- Accelis. While Ultrium was provided for data backup, Accelis should serve archiving. Accelis should therefore allow a much faster access to individual files. However, it is never gone beyond the stage of development and were discarded prior to launch. Was brought to the market ultimately only LTO Ultrium.
Another special feature of LTO is that a continuous development process was planned from the beginning. Every two years, to a new generation of products offered on the state of the art in which doubled the tape capacity and data transfer rate is also doubled or at least increased by 50 %. Drives can process bands of the previous generation and read the penultimate generation of bands at least. Since Generation 4 LTO consortium is fallen somewhat into delays. Currently, LTO Ultrium is available in generations 1 to 6.
Since Generation 3 WORM tapes are available that do not allow overwriting. This write protection is enshrined in the firmware of the drives and is activated by the properties of the inserted tape. Not every drive the generation 3 or later must support WORM tapes.
Since Generation 4 bands can also be encrypted regardless of the manufacturer. For this purpose, drive and tape at least from the Generation 4 need to be. This key is according to the AES algorithm with 256 bit in Galois Counter mode of operation is encrypted ( AES256 -GCM ). The implementation of the method is in accordance with IEEE specification. The performance is not affected or only slightly ( 1%). Key management is not a part of the Linear Tape-Open standards. It may be part of the tape library, the ( backup ) application or a standalone program. Thus can also be influenced by whether and what parts of the recording are encoded on a tape. Not every drive the generation 4 or later must support encryption.
With the generation of the Linear Tape File System 5 has been introduced. The drives are thus in a position to create two partitions on each band, one of which contains the metadata of the other. The metadata is captured in the Extensible Markup Language (XML). Bands with the Linear Tape File System can therefore be self-explanatory. The specification is open source.
Meanwhile, (3.5 inch) are also half-height drives ( 1.75 inches how many optical drives) produced next to the drives in full, the maximum transfer rates are usually about 20-35 % less.
Ultrium tapes feature similar to AIT tapes over a semiconductor memory in the cartridge case. In this 32 kilobits (4 kB) large memory chip, among other things, the serial number of the tape and the Nutzungslogdateien the last 100 tape mounts are stored.
The Ultrium cartridges measuring 102.0 × 105.4 × 21.5 mm. In the development of LTO ultrium tapes specially thought has been given to the requirements of automated data backup. So have the ultrium tapes on a slight wedge shape and special notches, making it easier for a robot to take the tape. The wedge shape is useful when robotics the belt placed in the drive, since the offset tolerance is increased by the wedge shape. LTO Ultrium tape libraries are available in sizes from 1 TB to just over 10 PB. LTO Ultrium drives can also be connected to storage area networks via SCSI or SAS to hosts via iSCSI or Fibre Channel.
The servo information is needed to LTO tapes are written only during manufacture, similar disks. Are deleted or damaged by a strong magnetic field, a tape is unusable.
The typical power consumption of LTO3 or LTO4 tape drive is below 20 W in operation and under 5 W in standby mode. These values are dependent on the manufacturer.