User Manual

SCSI Commands Reference Manual, Rev. J 385
www.seagate.com Parameters for direct access devices
PS (parameters saveable) bit
1 When using the MODE SENSE command, a parameters saveable (PS) bit set to one indicates that the mode page may be saved by the
logical unit in a nonvolatile, vendor specific location.
0 A PS bit set to zero indicates that the device server is not able to save the supported parameters. When using the MODE SELECT com-
mand, the PS bit is reserved.
DS bit
The DS bit is described in 5.2.2.
SPF (SubPage Format) bit
0 A SubPage Format (SPF) bit set to zero indicates that the page_0 mode page format is being used.
1 A SPF bit set to one indicates that the SUB_PAGE mode page format is being used.
PAGE CODE and SUBPAGE CODE fields
The PAGE CODE and SUBPAGE CODE fields identify the format and parameters defined for that mode page. Some page codes are defined as
applying to all device types and other page codes are defined for the specific device type. The page codes that apply to a specific device type
are defined in the command standard for that device type. The applicability of each subpage code matches that of the page code with which it
is associated.
When using the MODE SENSE command, if page code 00h (vendor specific mode page) is implemented, the device server shall return that
mode page last in response to a request to return all mode pages (page code 3Fh). When using the MODE SELECT command, this mode page
should be sent last.
PAGE LENGTH field
The PAGE LENGTH field specifies the length in bytes of the mode parameters that follow. If the application client does not set this value to the
value that is returned for the mode page by the MODE SENSE command, the command shall be terminated with CHECK CONDITION status,
with the sense key set to ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD IN PARAMETER LIST. The logical unit may imple-
ment a mode page that is less than the full mode page length defined, provided no field is truncated and the PAGE LENGTH field correctly
specifies the actual length implemented.
MODE PARAMETERS
The MODE PARAMETERS for each mode page are defined in the following subclauses, or in the mode parameters subclause in the command
standard for the specific device type. MODE PARAMETERS not implemented by the logical unit shall be set to zero.