magnetic tape cartridge (tape cartridge) A casing containing one or more reels carrying a length of magnetic tape, so arranged that it can be loaded on a suitable tape transport for access without the tape being handled by the operator. There are many forms of tape cartridge, some containing both the file reel on which the tape is wound and the take-up reel, and some the file reel only. The term is also used to describe a file reel without a separate casing but with some other provision, such as a special leader to protect the tape and avoid the need for the operator to touch it.

The best-known forms of tape cartridge are as follows.

(a) The autoload cartridge, introduced by IBM and consisting essentially of a collar clamped around the periphery of a standard 10½ reel of ½ wide magnetic tape. Its purpose is to facilitate autothreading of tape on suitably equipped tape transports. The reel can be removed from the cartridge for use on other transports.

(b) The DC300 cartridge, introduced by 3M and consisting of a metal and plastic casing containing two small reels of ¼ wide magnetic tape. Variants of this cartridge carry 300, 450, or 600 feet of tape in similar housings; the latter two are the DC450 and DC600 cartridges. DC1000 and DC2000 cartridges are similar but smaller. All these cartridges are used mainly on small computers in an office environment.

(c) The digital cassette, based on the standard audio cassette developed by Philips and made to similar dimensions though with more precision.

(d) Various designs of cartridge containing a relatively short length of wide tape on a single reel, used in automated tape libraries.

(e) Cartridges consisting of a few hundred feet of ½ wide tape on a single reel permanently mounted in an outer casing, with a coupling attached to the outer end of the tape to allow the end to be drawn out and mechanically loaded into the tape path of a suitable cartridge tape drive. The most widely used design is the 3480 cartridge, introduced by IBM in 1984 for its 3480 cartridge tape drive and since adopted by other manufacturers.

(f) Cartridges consisting of small (typically 3 or 4 diameter) reels of ½ tape without an outer casing, but with a tough protective leader slightly wider than the tape so that it gives full protection when wound onto the reel.