Dell PowerVault ML6000 - Manual (Page 39)

PowerVault ML6000 SCSI Reference Guide 29
Mode Select (6) - 15h
What the Library Does With This Command
The library does not support any changeable parameters, and this command is supported for compatibility
only. This command can be issued to both the Controller logical unit as well as a Media Changer logical unit.
The mode pages supported by each device vary however.
Command Usage
A MODE SENSE command with the PC field set to 1h and the Page Code field set to 3Fh can be issued
before the MODE SELECT command is issued to determine which mode parameters are supported, which
mode parameters are changeable, and the supported length of each page. Since the library does not
support any changeable parameters, use of MODE SELECT provides limited value. For a list of available
mode pages, see
Table 36 on page 37.
Mode Select (6) CDB Format
The six-byte MODE SELECT CDB format is shown in the following table.
Page Format (PF) - This bit indicates that the data sent by the initiator after the MODE SELECT header
and block descriptors complies with the definition of pages in the SCSI standard. The value must be set to 1.
Save Parameters (SP) - Savable pages are not supported and this field must be set to 0.
Parameter List Length - This field specifies the number of bytes that will be transferred for the MODE
SELECT parameter list, and should be equal to the length of a single Parameter List Header plus the lengths
of all pages to be transferred. A length of zero indicates that no data is transferred. This is not considered
to be an error.
Table 26 MODE SELECT CDB format
Bit
Byte
7 6 5 4 3 2 1 0
0 Op Code (15h)
1 Logical Unit Number PF Reserved SP
2 PC Page Code
3 Reserved
4 Reserved
5 Parameter List Length
6 Control