Glossary
SCSItape
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Glossary
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Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Block
Alternative name for a record.
BOM
Beginning of Medium: The first location on the medium which can be accessed.
BOP
Beginning of Partition: The first location in a partition which can be accessed. Identical to BOM if only one partition is defined.
BOT
Beginning of Tape: Same as BOM.
DDS
Digital Data Storage: The data-storage equivalent of the Digital Audio Tape (DAT). A recording medium consisting of a tape cartridge containing a supply and take-up reel and a quantity of magnetic tape of width 4mm. Data is recorded using a helical-scan technique.
DLT
Digital Linear Tape: A recording medium consisting of a tape cartridge containing a supply reel and a quantity of magnetic tape.
Early Warning
A location on the medium before EOM, defined by the tape drive. When a write operation encounters early-warning, there should be enough space left before EOM to accommodate all data still buffered by the drive (but not much more!)
EOD
End of Data: The location after the last record or tape mark on the medium resp. in a partition.
EOM
End of Medium: The last location on the medium which can be accessed. Used synonymously with EOP.
EOP
End of Partition: The last location in a partition which can be accessed. Identical to EOM if only one partition is defined.
EOT
End of Tape. The physical end-of-tape is synonymous with EOM, while logical end-of-tape is another name for the Early Warning position.
Filemark
A tape mark typically placed after the last record of a file to indicate its end. By convention, two successive filemarks are used to indicate EOD for some kinds of media.
Microdrive
One of the ingenious inventions of Sir Clive Sinclair. A tape drive mechanism using a miniature cartridge containing an endless loop of tape. Used with the Sinclair ZX Spectrum and QL computers. Total storage capacity of cartridge approx. 85KB.[1]

Recently, also the name of a miniature hard-disk drive by IBM. I hope Amstrad will sue the pants off those cheeky bastards.

Partition
The usable region of the recording medium, or a portion thereof. The SCSItape driver currently supports tapes with one or two partitions, but doesn't allow changing the number of partitions.
QIC
Quarter Inch Cartridge: A type of recording medium consisting of a tape cartridge containing a supply and take-up reel and a quantity of magnetic tape of width 0.25in (whence the name). Data is recorded in linear tracks, using a serpentine motion. There are many QIC standards in existence, specifying different recording formats, densities and track counts.
Record
The basic unit of user data stored on a tape. The length of a record depends on the capabilities of the drive mechanism; many drives support a large range of record sizes. Also called block.
Reel-to-Reel
A tape drive mechanism which doesn't use cartridges. Usually used to denote drives for 0.5in tapes. Not commonly found around PCs.
Setmark
A type of tape mark supported by some drives. Setmarks are hierarchically superior to filemarks and can be used for grouping. There are no universal conventions for the use of setmarks.
Tape Mark
A special marker placed on the medium, containing no user data.
Volume
The recording medium plus its physical carrier (reel or cartridge).

[1] But it was really neat for its time. At least, I and lots of Sinclair enthusiasts thought so.


Copyright © 1998 Jens Kilian. This file may be distributed under the conditions of the GNU General Public License.
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