HP C1537A, Technical Reference Manual

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56 glossary
ANSI American National Standards Institute, which sets standards for, amongst
other things, SCSI and the safety of electrical devices.
BOM Beginning Of Media. The first point on the tape that can be accessed by the
drive.
buffered mode A mode of data transfer in write operations that facilitates tape streaming. It is
selected by setting the Buffered Mode Field to 1 or 2 in the SCSI
MODE SELECT
Parameter List header.
compression A procedure in which data is transformed by the removal of redundant
information in order to reduce the number of bits required to represent the
data.
compression ratio A measure of how much compression has occurred, defined as the ratio of
the amount of uncompressed data to the amount of compressed data into
which it is transformed. The LTO-DC algorithm can typically achieve a
compression ratio of between 2:1 and 4:1 depending on the nature of the
data.
decompression A procedure in which the original data is generated from compressed data.
ECMA European Computer Manufacturers Association. The European equivalent of
ANSI.
EOD End Of Data. An area that signifies the end of the valid data. If new data is
written over a larger quantity of old data, it is possible for data to exist after
EOD, but because it is after EOD, this old data is no longer valid.
EOM End Of Media format. The last usable point on the tape.
EW-EOM Early Warning End Of Media. A physical mark or a device-computed
position on the tape that tells the drive that it is approaching EOM.
filemark A mark written by the host. It does not necessarily separate files; it is up to the
host to assign a meaning to the mark.
filemark count A mark written by the host. It does not necessarily separate files; it is up to the
host to assign a meaning to the mark.
FRU Field Replaceable Unit, an assembly or group of components that is replaced
in its entirety by Service Engineers when it contains a fault.
hard error An uncorrectable data error.