Inquiry - 12h, What the library does with this command, Command usage – Dell PowerVault ML6000 User Manual
Page 25: Inquiry cdb format, Table 9
PowerVault ML6000 SCSI Reference Guide
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Inquiry - 12h
What the Library Does With This Command
In response to this command the library returns static data that describes various subsystem parameters.
Each Controller and Media Changer logical unit will return its own Inquiry data. If an INQUIRY command is
received from an initiator with a pending unit attention condition, the library will perform the INQUIRY
command and will not clear the unit attention condition. An INQUIRY command will respond with a Check
Condition status only when it cannot return the requested Inquiry data.
Command Usage
This command would normally only be issued once for each logical unit as desired by the initiator to facilitate
the initialization process.
Inquiry CDB Format
The INQUIRY CDB format is shown in the following table.
Command Support Data (CMDDT) – This field is not supported and must be set to 0.
Enable Vital Product Data (EVPD) – An EVPD value of 1 indicates that the vital product data specified by
the Page Code should be returned. A value of 0 indicates that standard inquiry data should be returned.
Page Code - This field specifies which vital product data page to return if the EVPD bit is set to 1. If the
EVPD bit is set to 0, the Page Code must be 00h. The library supports the following page codes:
•
00h - Supported Vital Product Data pages (this list)
•
80h - Unit Serial Number page
•
83h – Device Identification page
Allocation Length - The Allocation Length field specifies the maximum number of bytes that the initiator
allocated for returned inquiry data. An Allocation Length of 0 indicates that no inquiry data is to be
transferred (this condition is not considered an error).
The library terminates the data transfer when it has transferred the lesser of either the number of bytes
specified by the Allocation Length field or all of the available inquiry data.
Table 9
INQUIRY CDB format
Bit
Byte
7
6
5
4
3
2
1
0
0
Op Code (12h)
1
Logical Unit Number
Reserved
CMDDT
EVPD
2
Page Code
3
Reserved
4
Allocation Length
5
Control