Inquiry
Inquiry
The INQUIRY command requests
that
information regarding parameters of the Target be sent
to
the Initiator.
The INQUIRY command will return a CHECK
CONDITION status only when the Target
cannot return the requested Inquiry data. Inquiry
data
will be returned even though the
peripheral device may not be ready for other commands. The
INQUIRY command will
execute even
if
the drive is reserved
to
another Initiator.
If
an INQUIRY command is received from an Initiator with a pending UNIT ATTENTION
condition (before the Target reports CHECK
CONDITION status), the Target will execute
the INQUIRY command and will not clear the
UNIT ATTENTION condition.
Note
9
Byte
00
An INQUIRY command directed to an invalid
LUN
(
=I
0) will return a
Peripheral Device Type of 7FH (Logical Unit Not Present) in byte 0 of
the
parameter list. This condition is not considered an error. The INQUIRY
command will be executed with no error reported even
if
the Target is
reserved by
Ito
a different Initiator.
Inquiry Command DeSCriptor Block
(COB)
Bit
7
I
6
I
5
I
4
I
3
I
2
I
1
I
0
Opcode = 12H
01
LUN
(Logical Unit Nwnber)
I
Reserved
I
EVPD
02
VPD Page Code
03
Reserved
04
Allocation Length
05
Control
Byte
EVPD (Enable Vital Product Data) and VPD Identifier. The
status
of
the EVPD bit and the
VPD Identifier field determine the information
to
be returned
to
the Initiator. The supported
combinations are:
EVPD
bit
o
1
1
1
VPD
Page
Code
OOH
OOH
SOH
EOH
Target
Will
Return:
Standard
Inquiry
Parameter
Page
Supported
VPD Page List
Unit Serial Number VPD
Page
Manufacturing Information VPD
Page
If
EVPD is set
to
0 (zero), and the VPD Page Code
is
set
to
1 (one),
the
Target will return:
Status:
CHECK CONDITION
Sense
Key: ILLEGAL REQUEST
Additional Sense Code: INVALID FIELD IN CDB.
Allocation Length. This field specifies the number of bytes
that
the Initiator has allocated for
returned Inquiry data. An Allocation Length of zero indicates
that
no INQUIRY
data
will be
transferred. This condition will not be considered as an error. Any other value indicates the
DRAFT
SCSI
Command Descriptions A·11
1/18/93
09:58
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