HP C2246 Technical Reference Manual page 77

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Mode Select, Mode Sense
Sense Data Length. This field specifies the length in bytes of the page data to be returned
during the Data In phase. The Sense Data Length field does not include itself nor does it
include the Block Descriptor length.
Media Type. Set to all zeros to indicate fixed disk.
WP {Write Protect). Indicates whether the drive is in the write protect mode: zero (0)
=
write protect disabled; one (1)
=
write protect enabled. The write protect mode is enabled
or disabled with bit 7 in the Mode Select command control byte: zero (0)
=
write protect
disabled; one (1) = write protect enabled.
DPOFUA. Indicates whether the target supports the cache control bits DPO (Disable Page
Out) and FUA (Force Unit Access) in the extended READ command. The target always
reports a one (1) indicating that only the FUA bit is supported.
Device Specific Parameters. Not used. Set to all zeros.
Block Descriptor Length. This field specifies the length in bytes of the Block Descriptor, and
does not include the Parameter Pages. The block descriptor length will be either 0 or 8. The
Block Descriptor specifies the media characteristics for the entire Logical Unit.
Density Code. Not used. Set to zeros.
Number of Blocks. Set to all zeros indicating that all blocks are set to same size.
Block Length. Indicates logical block size. Set to user configuration.
PS (Page Save). Indicates savable Mode Sense page when set to one (1). Ignored for Mode
Select.
Page Length. Indicates number of bytes remaining in specified page after Page Length field.
Parameter Specifications for Supported Pages
The following tables list the parameter formats for all supported pages, their respective
default values, and indicates whether the field values are changeable or non-changeable with
the Mode Select command. If a field is changeable, the allowable range is given. In addition,
the title block for each page indicates whether the page is savable.
SCSI Command Descriptions A-21