1 test unit ready command, 2 inquiry – FUJITSU MCJ3230SS User Manual
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4.3 SCSI Commands
C156-E224-01EN
4-11
4.3.1 TEST UNIT READY command
The TEST UNIT READY command checks whether a logical unit is ready to
operate.
Table 4.4 TEST UNIT READY command
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation Code (00h)
1
LUN
Reserved
2-5
Reserved
If the ODD power is on and the ODD is ready to operate, the command reports
GOOD status. If the ODD is not ready or an error condition remains in the device
even though the ODD is ready, the command reports CHECK CONDITION
status. When this command is executed, the ODD resets the sense data.
4.3.2 INQUIRY
Table 4.5 INQUIRY command
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation Code (12h)
1
LUN
Reserved
2-3
Reserved
4
Allocation Length
5
Reserved
The ODD returns CHECK CONDITION status only when it fails to return the
INQUIRY data requested by the INQUIRY command.
When the ODD receives an INQUIRY command from INIT while it has a UNIT
ATTENTION condition (before the ODD reports CHECK CONDITION status),
the ODD executes the INQUIRY command but does not clear the UNIT
ATTENTION condition.
The transfer byte length field at CDB byte 4 indicates the number of bytes of
INQUIRY data that INIT can receive with this command. The ODD transfers as
many bytes of data as specified by the transfer byte length or the INQUIRY data
held by the ODD, whichever is smaller. If 0 is specified in the transfer byte length
field, the command ends and no data is transferred.