Sony DDS-4, Руководство по описанию продукции

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6 - 102 SONY SDT-10000/SDT-11000 DDS Tape Drive
6. COMMAND SPECIFICATION
Bit 7 6 5 4 3 2 1 0
Byte
0 Operation Code (10h)
1 Logical Unit Number Reserved WSmk Immed
2 (MSB)
3 Number of Filemarks or Setmarks
4 (LSB)
5 Unused (00b) Reserved
6. 29 WRITE FILEMARKS 10h
WRITE FILEMARKS causes the specified number of Filemarks or Setmarks to be written, beginning at the current
logical position on tape.
WSmk:
If this bit is set, the drive writes a Setmark to tape instead of a Filemark.
Immed:
If this bit is set, the drive returns status as soon as the Command Descriptor Block has been validated. An Immed bit
of zero indicates that status will not be returned until the operation has completed. If the drive is in Unbuffered
Mode and the Immed bit is set, the drive will return a CHECK CONDITION status with an ILLEGAL REQUEST
sense key set.
Number of Filemarks or Setmarks:
This is the number of consecutive marks to be written to tape. A value of zero is not considered an error and GOOD
status is returned.
Note: The DDS format limits the number of Filemarks or Setmarks that may be written on a tape to a maximum of
65,536. If the drive is requested to write greater than this number of Setmarks, it returns a CHECK CONDITION
status with an ILLEGAL REQUEST sense key set.
This command may be used to force the drive to write any buffered data to the tape. If the drive is in Buffered Mode, and
a WRITE FILEMARKS command is received without the Immed bit set, the requested mark(s) will be appended to the
data and the write buffer will be flushed to tape. A zero value in the Number of Filemarks field indicates that no
Filemarks are to be written to the tape but the write buffer is still flushed to tape.
If EOT is detected while writing the marks, the drive will finish writing any buffered data. The command will terminate
with CHECK CONDITION status. Within the Sense data, the EOM bit is set, the Sense Key field is set to NO SENSE
and the Additional Sense Code and Additional Sense Code Qualifier fields are set to EOM/P detected. The drive will
attempt to complete any subsequent WRITE FILEMARKS, returning a CHECK CONDITION status in each case.
If the drive encounters the physical EOM when attempting a WRITE FILEMARKS, CHECK CONDITION status is
returned. Within the Sense data, the EOM and Valid bits are set and the Sense Key field is set to VOLUME OVER-
FLOW. The Information fields contain the residue count and the Additional Sense Code and Additional Sense Code
Qualifier fields are set to EOM/P Detected. The tape is physically positioned at EOM/P.
WRITE FILEMARKS