Linear Tape File System
The IBM Long Term File System (LTFS) is a self-describing tape format and file system software. It defines a self-describing format for storing files, organized in hierarchical directory structure on tape, and a file system software to format and mount LTFS tapes, create files and access them directly on tapes. With LTFS, tapes can be used independently of any external database or storage system. Files can be created on tape and accessed like creating and accessing files on a hard drive. Applications, such as file browsers, image viewers and media players can directly access files on tape. LTFS enables easy and simple use of data tapes in desktop computers and embedded systems [1].
History
Magnetic tapes have been used for over 50 years. Prior to the introduction of LTFS, tapes were primarily used within data storage systems. In a typical data storage system, tapes are stored in tape libraries. A central index of all the tapes in the library is kept on a server and is maintained by the storage system. Applications may interface the tape storage system through API-s, various NAS and SAN architectures, Hierarchical Storage Management (HSM) and more. Content is ingested and retrieved to the storage system in the form of files, data blocks, streams and objects. Tapes in the system may or may not contain an index of their content. The index format depends on the storage system and is generally not interoperable with other systems.
The Tape Archive (TAR)[2] is a file format designed to allow encapsulation of multiple files for tape storage. TAR includes the files content and an index with names and file metadata. TAR files allow to create self-describing tapes, however they do not provide easy access and use of individual files.
LTFS makes tapes self-describing, self-contained, portable storage media. It was first announced and made available by IBM on April 12 2010, and presented at the National Association of Broadcasters trade show, Las Vegas (NAB-2010). In its first release it supports the Linear Tape Open Ultrium 5 (LTO-5) drives and media. It is also referred to as the Linear Tape File System.
Technical Overivew
An introduction to LTFS is available on the IBM LTFS web site. LTFS refers to both the format of storing the data on tape (the LTFS Format) and a file system software which can be used to create and work with LTFS tapes. The LTFS Format is described in the specifications document. The LTFS Software is available as open source.
- ^ For example, see the FOR-A LTR-100HS Video Archive Recorder and deck player with HD/SD-SDI I/O
- ^ Tape Archive - the TAR (file format)