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When spacing over blocks or filemarks this field indicates how many blocks or marks
Count
should be crossed. Spacing is forward (towards EOM) unless Count is negative (twos
complement) when the spacing is towards BOM.
When spacing to EOD the Count field is ignored.
When not spacing to EOD, if Count is zero, the
operation. The logical position remains unchanged, and unwritten data is not flushed to
tape.
Lowest priority Blocks
Filemarks
EOD
BOM
Highest priority EOM
Space Specific Status:
If the drive fails to space either from a medium error or from some sort of non-
fatal drive error,
CHECK CONDITION
set to
. Additional sense depends on the nature of the error.
MEDIUM ERROR
The two most common additional sense code and qualifiers in this case will
be: 1100h (unrecovered read error) and 3B00h (sequential positioning error).
The drive implements the following priority scheme when a tape position point
is encountered:
If the drive meets a filemark while spacing to a block
reported. The Mark bit in the sense data is set, and the sense key is
Additional sense is 0001h (filemark encountered). The final position will be
before or after the filemark depending on whether the space was reverse or
forward.
If the drive meets EOD while spacing to a block or mark,
reported. The EOM bit in the sense data is set. The sense key is
additional sense is 0005h (EOD encountered).
If the drive meets BOM while spacing,
bit and Valid bit in the sense data are set to 1 and the information bytes set to the
total number of blocks or filemarks that remain to be spaced over (in other words,
the requested number minus the number that have been spaced over). The sense
key is
and additional sense is 0004h (BOT detected).
NO SENSE
If the drive meets EOM while spacing,
bit in the sense data is set. The sense key is
0002h (EOP/M detected).
If "blank media" is encountered during a space (in other words, the drive
attempted to space on an unformatted tape), the drive behaves as if EOD
was at BOM. It will then respond with
EOD, and with
CHECK CONDITION
Additional sense is set to 1403h (
command is treated as a null
SPACE
status is reported. The sense key will be
CHECK CONDITION
CHECK CONDITION
is reported. The EOM
CHECK CONDITION
is reported. The EOM
CHECK CONDITION
and additional sense is
MEDIUM ERROR
status to a request to space to
GOOD
to any other forward spacing request.
).
End of data not found
is
.
NO SENSE
is
and
BLANK CHECK
Commands 149
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