Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
152
18.8
MODE SELECT (15)
Table 125 Mode Select (15)
Byte
Bit
7
6
5
4
3
2
1
0
0
Command Code = 15h
1
Reserved = 0
PF=1
Reserved = 0
SP
2
3
Reserved = 0
4
Parameter List Length
5
VU = 0
Reserved = 0
FLAG
LINK
The MODE SELECT (15) command provides a means for the Initiator to specify LUN or device parameters to the
Target. It also allows an Initiator to specify options the Target uses in error recovery, caching, and formatting.
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 Save Pages. This indicates
- 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 an error.
- 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.
The MODE SELECT parameter list contains a 4-byte header followed by zero or one block descriptor followed by
zero or more pages. The pages that 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) 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 the same value as returned by the drive in MODE SENSE Page Length. If not, the drive will return Check
Condition status with sense key of Illegal Request.
Note: If an Initiator sends a MODE SELECT command that changes any parameters that apply to other Initiators,
the drive shall generate a unit attention condition for all Initiators except for the one that issued the MODE SELECT
command. The drive shall set the additional sense code to Parameters Changed (2Ah).