Fujitsu MCJ3230SS manual Test Unit Ready command, Inquiry command

4.3 SCSI Commands

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	7	6	5		4		3	2	1	0
Byte
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	7	6	5		4		3	2	1	0
Byte
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.

C156-E224-01EN 4-11