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 standards alternative to the proprietary magnetic tape formats that were 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 2021, LTO-9, can hold 18 TB in one cartridge.
A 400 GB LTO-3 cassette by Sony
An LTO-2 mechanism, from IBM. This SCSI drive fits in a 5.25 inch, Full-Height drive bay.
LTO-2 cartridge with the top shell removed, showing the internal components. Top right corner: tape access gate. Bottom left corner: write-protect-tab. Bottom right corner: cartridge memory chip
LTO-3 cartridge with the top shell removed, showing the internal components. Top right corner: write-protect-tab. Bottom left corner: cartridge memory chip. Bottom: tape access gate.
IBM's first magnetic-tape data storage devices, introduced in 1952, use what is now generally known as 7-track tape. The magnetic tape is 1⁄2 inch (13 mm) wide, and there are six data tracks plus one parity track for a total of seven parallel tracks that span the length of the tape. Data is stored as six-bit characters, with each bit of the character and the additional parity bit stored in a different track.
Reel of 1/2" tape showing beginning-of-tape reflective marker
A write-protection ring had to be inserted in the back of a reel to allow its tape to be written on.
A reel of half-inch magnetic tape being loaded onto an IBM 729 tape drive that is attached to an IBM 1401 being restored at the Computer History Museum.