Magnetic Tape Cartridge (tape cartridge) Definition/Meaning:
A casing containing one or more reds
carrying a volume 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 and the take-up reel (see magnetic tape) 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 or Easyload cartridge, introduced by IBM and
consisting essentially of a collar clamped around the periphery of a
standard 10 and 1/2" reel of 1/2" 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 1/4" wide magnetic tape. The cartridge is
used in a transport whose heads protrude through a window in the cartridge to
make contact with the tape as it passes from one reel to the other. Variants of
this cartridge carry 300, 450, or 600 feel of tape in similar housings. It is
usual for the drive to record several tracks of data on the tape, one at a time
(i.e. serially); a number of different tape formats are used and at least one
of these is now defined by an ANSI Standard. This type of cartridge, and the
similar but smaller DC100 type, is 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. The plastic
casing contains two small reels of tape 0.15" wide, in various lengths, and is
used in a
transport whose heads protrude through a window in the cartridge to make contact
with the tape. The tape is moved by direct contact with a capstan against which
it is pressed by a pinch roller, both being part of the transport; the transport
also connects mechanically to the hubs of both reels to control the winding and
unwinding of the tape. Cassette tape is now used mainly on hobbyist computers
and these often use standard audio cassettes and decks rather than the
higher-quality digital variety.
(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 small (typically 3" or 4" diameter) reels of
1/2"
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.
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