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6.Command Specification
6.3. LOAD/UNLOAD 1Bh
Bit
7
Byte
0
1
Logical Unit Number
2
3
4
5
Unused (00b)
LOAD/UNLOAD allows the host to tell the drive to enable or disable the media for further operations.
Load: When this bit is set, the drive loads the tape and positions it at the beginning of Partition 0. The load command
is used when the tape has been retained in the drive by the command sequence, Prevent Allow Media Removal(with
prevent bit set), Unload. The drive will automatically perform a Load operation when a tape is inserted, a SCSI Reset
is received, or when power is restored with a tape in the drive. If the bit is not set (UNLOAD), the drive writes any
buffered data to the tape, writes the EOD, then rewinds the tape to BOM and ejects it.
Immed: If this bit is set, status is returned as soon as the load or unload operation is initiated. Otherwise, the status
is returned after the operation has completed.
Re-Ten: If this bit is set, the drive winds to EOM then rewinds to BOM before starting a normal loading sequence.
EOT: An end-of-tape (EOT) bit of one and a Load bit of ZERO indicates that the medium shall be positioned at
end-of-medium for removal from the peripheral device. Prior to performing the unload operation, any buffered data
that is to be written shall be transferred to the medium. An EOT bit of ZERO and Load bit of ZERO indicates that the
medium shall positioned at beginning-of-medium for removal etc. An EOT bit of one and a Load bit of one shall
cause the target to return CHECK CONDITION status. The sense key shall be set to ILLEGAL REQUEST and the
additional sense code shall be set to ILLEGAL FIELD IN CDB.
If the drive has received an UNLOAD command with the Immediate bit set and then receives either another
command which would involve tape motion or TEST UNIT READY, the drive will return a CHECK CONDITION
status with a NOT READY sense key set.
When the drive receives the UNLOAD, it updates the System area of whichever partition on the tape is currently
active. The tape is then rewound to BOM and ejected. The operator must reload the drive manually. If, however, the
drive has previously received a
PREVENT MEDIA REMOVAL (with prevent bit set) command, the tape is retained in the drive. A subsequent LOAD
command will load and position the tape at BOP ZERO. If an UNLOAD were sent instead, the drive would return
NOT READY and the tape would remain within the drive. In this case, the drive requires an PREVENT ALLOW
MEDIA REMOVAL (with prevent bit clear) command before an UNLOAD will eject the tape.
Note: While the PREVENT MEDIA REMOVAL is in effect, the Front Panel EJECT button is completely disabled.
If the cassette is unloaded but has not been ejected from the drive because of moisture detection, then a subsequent
UNLOAD will cause the tape to ejected from the drive. All commands except INQUIRY, REQUEST SENSE and
READ BLOCK LIMITS will return a CHECK CONDITION status with a HARDWARE ERROR sense key set. The
tape may also be ejected via the Front Panel EJECT button.
If no cassette is in drive, both LOAD and UNLOAD will return a CHECK CONDITION status with NOT READY sense
key set
6-8
6
5
4
Operation Code (1Bh)
Reserved
3
2
Reserved
Reserved
Reserved
EOT
Reserved
SONY AIT-E Turbo drive SDX-250V series Ver.1.0
LOAD/UNLOAD
1
0
Immed
Re-Ten
Load
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