Linear Tape-Open

Linear Tape-Open (LTO), also known as the LTO Ultrium format, is a magnetic tape data storage technology used for backup, data archiving, and data transfer. It was originally developed in the late 1990s as an open-standard alternative to the proprietary magnetic tape formats available at the time. Upon introduction, LTO rapidly defined the super tape market segment and has consistently been the best-selling super-tape format. The latest generation as of 2026, LTO-10, defines two unique cartridge types which can hold 30 TB or 40 TB each.

Cartridges (a.k.a. tapes) contain hundreds of meters of half-inch (12.65 mm) wide tape media wound onto a single reel. The first generation LTO cartridge was released in 2000 and stored 0.1 TB of data. With each new generation, the capacity has increased, while maintaining the same physical size cartridge.

Mechanisms (a.k.a. drives, streamers, transports) extract the tape from the cartridge and spool it up on a second reel in the mechanism, reading or writing data as the tape moves between reels. Robotic libraries exist that can hold hundreds or thousands of LTO cartridges and dozens of mechanisms.

In contrast to other non-tape data storage formats, LTO offers high-capacity removable cartridges with a lower cost per TB and better long term stability. As an overall system, LTO requires significantly less electrical power per TB and includes built-in technologies useful for data interchange and safe-keeping, like LTFS, WORM, encryption and data compression.