Section 5
SCSI Programming Guidelines
5.11.9
INQUIRY COMMAND: OPCODE = 12(hex)
The INQUIRY command (Table 5-21) requests that information regarding identification
of
the target be sent
to the initiator.
5.11.9.1
CQmmand Structure
TABLE
5-21
INQUIRY
Command
Bit 7
I
6
I
5
I
4
I
3
I
2
I
1
I
Byte
0
OPCODE=
12H
1
LUN=O
I
RESERVED
=0
2-3 RESERVED
=0
4
ALLOCA
nON
LENGnt
(BYTES)
5
VU=O
I
RESERVED =
O·
I
F
I
ALLOCATION LENGTH - Specifies the maximum number
of
bytes that the initiator has
allocated for returned
IN
QUIR Y data. A value
of
00 indicates that no data will be returned.
Acceptable values are
OO-FFH.
The ProDrive will terminate the DATA IN phase when the
0
L
allocation length bytes have been transferred
or
when all available INQUIRY data have been transferred
to the initiator, whichever is less. (For the
ProDrive, an allocation length
of
130 (82H) is
recommended.)
5.11.9.2
INQUIRY DATA Format
TABLE
5-22
INQUIRY
DATA
Format
Bit 7
I
6
I
5
I
4
I
3
I
2
I
1
1
0
Byte
0
PERIPHERAL DEVICE TYPE
= 0
1
RMB=O
I
DEVICE TYPE QUALIFIER = 0
2
RESERVED
=0
I
ECMA VERSION = 0
I
ANSI VERSION = 1
3
RESERVED=O
I
RESPONSE DATA FORMAT = 1
4
ADDmONAL
LIST
LENGnt
PERIPHERAL DEVICE TYPE (Byte 0) - Set to a value
of
zero for the ProDrive
(Direct
Access Device), unless the LUN specified in the Command Descriptor Block is invalid.
If
the LUN
is
invalid~
the peripheral device
type
is set to 7FH. The reset
of
the data bytes is not affected and are
returned as
if
the LUN was set to a value
of
zero.
RMB - REMOVABLE MEDIUM BIT (Byte
1,
Bit 7) - Always set to zero for the
ProDrive
to
indicate non-removable media.
DEVICE TYPE QUALIFIER (Byte 1, Bits 6-0) - Not supported by ProDrive; it is set to
a value
of
zero.
SCSI
Programming
Guidelines
5·39
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