SCSI Description
￿￿￿￿+037+4;The INQUIRY￿%QOOCPFcommand￿￿￿￿Jallows￿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 5-22and Table 5-23.
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.
INQUIRY Command Descriptor Block-Data Format

 

 

 

 

 

 

 

 

 

 

 

 

Operation Code (12h)

 

 

 

 

 

 

 

 

1

 

 

Reserved

CmdDt

EVPD

 

 

 

 

 

 

2

 

 

Page Code or Operation Code

 

 

 

 

 

 

 

 

 

3

 

 

 

Reserved

 

 

 

 

 

 

 

 

 

4

 

 

 

Allocation Length

 

 

 

 

 

 

 

 

 

5

 

 

 

Control

 

 

 

 

 

 

 

 

 

 

 

$[VG$KV

￿

 

INQUIRY￿

Command￿

Descriptor￿

Block￿-Field Descriptions￿

￿

￿

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Command Support Data. If CmdDt = 0 and EVPD (see below) = 0, the drive

CmdDt(KGNF

 

 

 

returns the Standard Inquiry Data&GUETKRVKQP. If CmdDt = 1 with EVPD = 0, the drive

 

 

 

 

returns the Command Data specified by Page Code/Operation.

 

 

 

 

 

 

 

Table

 

Enable Vital Product Data. If EVPD = 0 and CmdDt (see above) = 0, the drive

EVPD

 

returns the Standard Inquiry Data. If EVPD = 1and CmdDt = 0, the drive re-

 

 

turns the Vital Product Data Page specified by Page Code/Operation Code.

 

5-22

 

 

 

 

 

 

 

 

 

 

Specifies the Vital Product Data Page or Command Support Data which is to

 

 

 

 

be returned by the drive when EVPD is set. Specifies the SCSI Operation Code

Page Code or

 

 

for command support data to be returned by the drive when CmdDt is set. A

 

 

CHECK CONDITION status is returned if this field specifies an unsupported

Operation Code

 

 

 

 

Page or Operation Code or if both EVPD and CmdDt are set. Table 5-27lists

 

 

 

 

 

 

 

 

the Page Codes for the Vital Product Pages supported by the drive. Table 5-

 

 

 

 

41 lists the operation codes for the CmdDt information supported by the

 

 

 

 

drive.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Specifies the number of bytes of inquiry information the drive is allowed to

Allocation Length

 

 

return to the initiator during the command's data-in buffer transfer. Error sta-

 

 

tus is not returned if the value in this field truncates the requested informa-

 

Table5

 

 

-23tion.

 

 

 

 

 

 

5-20 Maxtor Atlas 10K III

Page 84
Image 84
Maxtor 10K III manual Operation Code 12h Reserved CmdDt, Evpd, Code or Operation Code, Allocation Length Control