Linear Tape-Open (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. Hewlett Packard Enterprise, IBM and Quantum control 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 can hold 100 GB of data in a cartridge. The seventh generation of LTO Ultrium was released in 2015 and can hold 6.0 TB in a cartridge of the same size.
Upon introduction, LTO Ultrium rapidly defined the super tape market segment and has consistently been the best-selling super tape format. LTO is widely used with small and large computer systems, especially for backup.
Half-inch (½-inch, 12.65 mm) magnetic tape has been used for data storage for more than 60 years. In the mid 1980s, IBM and DEC put this kind of tape into a single reel, enclosed cartridge. Although the physical tape was nominally the same size, the technologies and intended markets were significantly different and there was no compatibility between them. IBM called its format 3480 (after IBM's one product that used it) and designed it to meet the demanding requirements of its mainframe products. DEC originally called theirs CompacTape, but later it was renamed DLT and sold to Quantum Corporation. In the late 1980s, Exabyte's Data8 format, derived from Sony's dual-reel cartridge 8 mm video format, saw some popularity, especially with UNIX systems. Sony followed this success with their own now-discontinued 8 mm data format, Advanced Intelligent Tape (AIT).
By the late 1990s, Quantum's DLT and Sony's AIT were the leading options for high-capacity tape storage for PC servers and UNIX systems. These technologies were (and still are) tightly controlled by their owners. Consequently, there was little competition between vendors and the prices were relatively high.