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Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
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Deferred errors may indicate that an operation was unsuccessful long after the command performing the
data transfer returned GOOD status. If data that cannot be replicated or recovered from other sources is
being stored using such buffered write operations, synchronization commands should be performed before
the critical data is destroyed in the host initiator. This is necessary to be sure that recovery actions can be
taken if deferred errors do occur in the storing of the data. When AEN is not implemented, the synchronizing
process provides the necessary commands to allow returning CHECK CONDITION status and subsequent
returning of deferred error sense information after all buffered operations are guaranteed to be complete.
5.1.1.3
Inquiry Command (12h)
The INQUIRY command requests that information regarding parameters of the disc drive be sent to the
initiator. An option Enable Vital Product Data (EVPD) allows the initiator to request additional information
about the disc drive. See paragraph 5.1.1.3.1. Several Inquiry commands may be sent to request the vital
product data pages instead of the standard data shown in Table 5.1.1-8.
Table 5.1.1-7. Inquiry command (12h)
Bit
7
6
5
4
3
2
1
0
Byte(s)
0
0
0
0
1
0
0
1
0
1
Logical Unit No.[1]
0
0
0
0
0
0
0
EVPD [2]
2
Page Code
[3]
3
0
0
0
0
0
0
0
0
4
Allocation Length In Bytes
[4]
5
0
0
0
0
0
0 Flag
Link [5]
Notes.
[1] LUN must be zero.
[2] An enable vital product data (EVPD) bit of one specifies that the disc drive shall return the vital product
data specified by the page code field. An EVPD bit of zero specifies that the disc drive shall return the
standard INQUIRY data.
[3] The page code field specifies the page of vital product data information that the disc drive shall return. If
the EVPD bit is zero and the page code field is not zero the disc drive shall return CHECK CONDITION
status with the sense key set to ILLEGAL REQUEST and an additional sense code of INVALID FIELD IN
CDB.
[4] The Allocation Length specifies the number of bytes that the initiator has allocated for returned data. The
disc drive shall terminate the Data-In phase when Allocation Length bytes have been transferred or when
all available data have been transferred to the initiator, whichever is less.
[5] See “Control Byte” paragraph 4.2.6.
The INQUIRY command returns CHECK CONDITION status only when the disc drive cannot return the
requested INQUIRY data.
If an INQUIRY command is received from an initiator with a pending unit attention condition (i.e., before the
disc drive reports CHECK CONDITION status), the disc drive performs the INQUIRY command and does not
clear the unit attention condition.
