Hitachi DK32EJ - Ultrastar Series 36.9 GB Hard Drive Reference Manual page 162

The Page Length field specifies the number of bytes that follow the page length field.
The Page Length field must be loaded with a page length value that is supported by
the controller. This value is reported by the controller to the host computer by
checking it in the page length field of the Mode Sense data.
The controller assumes and reports a contiguous page area even if the page contains
unsupported fields.
The host computer can transfer all pages supported by the controller including
unchanged pages. The page codes may be specified in any order.
Except the block descriptors are managed on a controller unit basis.
When value in these areas are changed, the controller reports the CHECK
CONDITION status with UNIT ATTENTION sense key to the first command sent by
any initiator other than the one that changed these value. The host computer must
load 0's into the corresponding fields and bits that are flagged as unchangeable in
the Mode Sense data.
Precautions to be observe on the host computer side
It is recommended that the host computer issue a MODE SENSE command
requesting the controller to return all changeable values prior to issuing any
MODE SELECT commands, in order to find out the pages supported by the
controller, page lengths, and changeable fields or bits.
It is recommended that the host computer issues the RESERVE UNIT command
prior to executing the MODE SELECT command which intends to change the page
3 (Format parameter) and/or page 4
H
RELEASE UNIT command after the completion of the FORMAT UNIT command.
This procedure will prevent another host computer from issuing different Mode
Select parameters to the same unit prior to the execution of the FORMAT UNIT
command.
MODE SELECT:(15h)
6 COMMAND DESCRIPTIONS
OEM MANUAL:K6602771
(Geometry parameter), and issues the
H
Revision: 2 / Date: 2002.12.19
Page: 162 / 313