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Smaller tape libraries with only one drive are known as autoloaders. The term ''autoloader'' is also sometimes used synonymously with ''stacker'', a device in which the media are loaded necessarily in a sequential manner.
Other types of autoloaders may operate with
In computer storage
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers.
The central processing unit (CPU) of a compute ...
, a tape library, sometimes called a tape silo, tape robot or tape jukebox
A jukebox is a partially automated music-playing device, usually a coin-operated machine, that will play a patron's selection from self-contained media. The classic jukebox has buttons, with letters and numbers on them, which are used to sele ...
, is a storage device that contains one or more tape drive
A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and a long archival stability. ...
s, a number of slots to hold tape cartridges, a barcode
A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or o ...
reader to identify tape cartridges and an automated method for loading tapes (a robot). Additionally, the area where tapes that are NOT currently in a silo are stored is also called a tape library. Tape libraries can contain millions of tapes.
One of the earliest examples was the IBM 3850
The IBM 3850 Mass Storage System was an online tape library used to hold large amounts of infrequently accessed data. It was one of the earliest examples of nearline storage.
History
Starting in the late-1960s IBM's lab in Boulder, Colorado ...
Mass Storage System (MSS), announced in 1974.
Design
These devices can store immense amounts of data, ranging from 20terabyte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...
s up to 2.1 exabyte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...
s of data as of 2016. Such capacity is multiple thousand times that of a typical hard drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with mag ...
and well in excess of what is capable with network attached storage. Typical entry-level solutions cost around $10,000 USD, while high-end solutions can start at as much as $200,000 USD and cost well in excess of $1 million for a fully expanded and configured library.
For large data-storage, they are a cost-effective solution, with cost per gigabyte as low as 2 cents USD. The tradeoff for their larger capacity is their slower access time, which usually involves mechanical manipulation of tapes. Access to data in a library takes from several seconds to several minutes.
Because of their slow sequential access and huge capacity, tape libraries are primarily used for backup
In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "back up", ...
s and as the final stage of digital archiving
A document management system (DMS) is usually a computerized system used to store, share, track and manage files or documents. Some systems include history tracking where a log of the various versions created and modified by different users is r ...
. A typical application of the latter would be an organization's extensive transaction record for legal or auditing purposes. Another example is hierarchical storage management
Hierarchical storage management (HSM), also known as Tiered storage, is a data storage and Data management technique that automatically moves data between high-cost and low-cost storage media. HSM systems exist because high-speed storage devices, ...
(HSM), in which tape library is used to hold rarely used files from file system
In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...
s.
Software support
There are several large-scale library-management packages available commercially. Open-Source support includesAMANDA
Amanda is a Latin feminine gerundive (i.e. verbal adjective) name meaning, literally, “she who must (or is fit to) be loved”. Other translations, with similar meaning, could be "deserving to be loved," "worthy of love," or "loved very much b ...
and the minimal mtx program.
Barcode labels
Tape libraries commonly have the capability of optically scanningbarcode
A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or o ...
labels which are attached to each tape, allowing them to automatically maintain an inventory of which tapes are where within the library. Preprinted barcode labels are commercially available or custom labels may be generated using commercial or free software. The barcode label is frequently part of the tape label, information recorded at the beginning of the medium to uniquely identify the tape.
Autoloaders
Smaller tape libraries with only one drive are known as autoloaders. The term ''autoloader'' is also sometimes used synonymously with ''stacker'', a device in which the media are loaded necessarily in a sequential manner.
Other types of autoloaders may operate with optical disc
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data ( bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surface ...
s (such as compact disc
The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in O ...
s or DVDs) or floppy disk
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined ...
s.
See also
* Optical jukeboxReferences
{{reflistLibrary
A library is a collection of materials, books or media that are accessible for use and not just for display purposes. A library provides physical (hard copies) or digital access (soft copies) materials, and may be a physical location or a vi ...