HP C737990900 - Manual (Page 149)

Commands 149
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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 status is reported. The sense key will be
set to MEDIUM ERROR . Additional sense depends on the nature of the 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 “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 GOOD status to a request to space to
EOD, and with CHECK CONDITION to any other forward spacing request.
Additional sense is set to 1403h ( End of data not found ).
Count
■
When spacing over blocks or filemarks this field indicates how many blocks or marks
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
SPACE
command is treated as a null
operation. The logical position remains unchanged, and unwritten data is not flushed to
tape.
Lowest priority Blocks
Filemarks If the drive meets a filemark while spacing to a block CHECK CONDITION is
reported. The Mark bit in the sense data is set, and the sense key is NO SENSE .
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.
EOD If the drive meets EOD while spacing to a block or mark, CHECK CONDITION is
reported. The EOM bit in the sense data is set. The sense key is BLANK CHECK and
additional sense is 0005h (EOD encountered).
BOM If the drive meets BOM while spacing, CHECK CONDITION is reported. The EOM
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 NO SENSE and additional sense is 0004h (BOT detected).
Highest priority EOM If the drive meets EOM while spacing, CHECK CONDITION is reported. The EOM
bit in the sense data is set. The sense key is MEDIUM ERROR and additional sense is
0002h (EOP/M detected).