Mode Select (15) - IBM Ultrastar 36LZX Specifications

8.10 MODE SELECT (15)

Byte
7 6
0
1 Reserved = 0
2
3
4
9 VU = 0
Figure 95. MODE SELECT (15)
The MODE SELECT (15) command provides a means for the initiator to specify LUN or device para-
meters to the Target. It also allows an Initiator to specify options the Target uses in error recovery and
Caching.
There is a single set of Mode Page parameters shared by all initiators.
PF A PF (Page Format) bit value of one indicates that the data sent by the Initiator after the Mode
Select Header and the Block Descriptor, if any, complies to the Page Format. The Target ignores
this field since it only accepts mode parameters in the Page Format.
SP Pages. This indicates
0 The drive shall not save the pages sent during the Data Out phase but will use them for
all following commands until the power is removed, a reset is received, or a new mode
select command is received.
1 The drive will save the data in the reserved area of the disk. It will be used for all the
following commands until another mode select command is issued. This information is
maintained over a power cycle or reset of the drive.
Parameter List Length
This specifies the number of bytes to be sent from the initiator. A parameter list length of zero
suppresses data transfer and is not considered as an error.
The MODE SELECT parameter list contains a four-byte header, followed by zero or one block descriptor
followed by zero or more pages. The pages which are valid with this command are defined in the
addendum under the heading Mode Select Data as they vary with the drive model.
Application Note
The initiator should issue a MODE SENSE command requesting all Changeable values (see PCF field in
byte two of the CDB in MODE SENSE (1A) on page 92) prior to issuing a MODE SELECT command.
This is necessary to find out which pages are implemented by the drive and the length of those pages.
In the Pages of the MODE SENSE command the drive will return the number of bytes supported for
each Page. The Page Length set by the initiator in the MODE SELECT command must be same value
Bit
5 4 3
Command Code = 15h
PF=1 Reserved = 0
Reserved = 0
Parameter List Length
Reserved = 0
Ultrastar 36LZX hard disk drive specifications
2 1 0
SP
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