5.9INQUIRY Command (12h)
The INQUIRY command allows the initiator to determine the kind of SCSI devices attached to its SCSI bus. It causes a device that is attached to a SCSI bus to return information about itself. The drive identifies itself as a Direct Access Storage Device that implements the applicable interfacing protocol. The drive does not need to access its storage medium to respond to the inquiry. The INQUIRY commands are described in Table
The drive can provide two categories of data in response to an INQUIRY command: Standard Inquiry Data and Vital Product Data. Standard Inquiry Data contains basic data about the drive, and Vital Product Data comprises several pages of additional data. Each Vital Product Data page requires a separate INQUIRY command from the initiator.
An INQUIRY command is not affected by, nor does it clear, a Unit Attention condition.
Table
Bit | 7 | 6 | 5 |
| 4 |
| 3 |
| 2 | 1 | 0 |
Byte |
|
|
| ||||||||
|
|
|
|
|
|
|
|
|
|
| |
0 |
|
|
|
| Operation | Code (12h) |
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
| |
1 |
|
|
| Reserved |
|
|
|
| CmdDt | EVPD | |
|
|
|
|
|
|
|
| ||||
2 |
|
|
| Page Code or Operation Code |
|
|
| ||||
|
|
|
|
|
|
|
|
|
| ||
3 |
|
|
|
|
| Reserved |
|
|
| ||
|
|
|
|
|
|
|
|
| |||
4 |
|
|
|
| Allocation Length |
|
|
| |||
|
|
|
|
|
|
|
|
|
| ||
5 |
|
|
|
|
| Control |
|
|
| ||
|
|
|
|
|
|
|
|
|
|
|
|
Table | |
|
|
Field | Description |
|
|
CmdDt | Command Support Data. If CmdDt = 0 and EVPD (see below) = 0, the drive returns the |
Standard Inquiry Data. If CmdDt = 1 with EVPD = 0, the drive returns the Command Data | |
| specified by Page Code/Operation. |
EVPD | Enable Vital Product Data. If EVPD = 0 and CmdDt (see above) = 0, the drive returns the |
Standard Inquiry Data. If EVPD = 1and CmdDt = 0, the drive returns the Vital Product | |
| Data Page specified by Page Code/Operation Code. |
| Specifies the Vital Product Data Page or Command Support Data which is to be returned |
Page Code or | by the drive when EVPD is set. Specifies the SCSI Operation Code for command support |
data to be returned by the drive when CmdDt is set. A CHECK CONDITION status is re- | |
Operation Code | turned if this field specifies an unsupported Page or Operation Code or if both EVPD and |
| CmdDt are set. Table |
| the drive. Table |
| drive. |
Allocation Length | Specifies the number of bytes of inquiry information the drive is allowed to return to the |
initiator during the command's | |
| value in this field truncates the requested information. |
Maxtor Atlas 10K V |