Quantum ATL SuperLoader ATL, User Manual

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Chapter 3 Media Changer Commands
Inquiry Command (12h)
32 Quantum ATL SuperLoader Software Interface Guide
Inquiry Command (12h)
3
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
SuperLoader identifies itself as a media changer that implements
the SCSI-2 protocol.
The media changer can provide three categories of data in
response to an INQUIRY command: Standard Inquiry Data, Vital
Product Data, and Command Support Data. Standard Inquiry
Data contains basic data about the device. Vital Product Data
comprises several pages of additional data. Each Vital Product
Data page requires a separate INQUIRY command from the
initiator. Command Support Data indicates the fields in the CDB
that are supported by opcode. An INQUIRY command is not
affected by, nor does it clear, a Unit Attention condition.
Figure 7 Inquiry
Command
Bit
Byte
7 6 5 4 3 2 1 0
0
Operation Code (12h)
1
Logical Unit Number Reserved CmdDt EVPD
2
Page Code
3
Reserved
4
Allocation Length
5
Unused Reserved Flag Link