5.12.2Mode Page Types

The drive maintains three distinct sets of mode pages. They are the current page, the default page, and the saved page. The drive also reports a fourth set of changeable pages. The page types are defined in Table 5-50.

 

Table 5-50Mode Page Types

 

 

Page Type

Definition

 

 

 

The current mode page set applies to all initiators and defines the drive’s mode. The SCSI-2 spec-

 

ification states that a drive can maintain Mode parameters on a per-initiator basis if it so chooses.

 

The Drives do not support this option.

 

The current mode page set contains the values supplied in the last MODE SELECT command re-

Current

ceived from an initiator. If no initiator has sent a MODE SELECT command since the drive was

last reset or powered up, the current pages contain

 

• Saved values if saved pages exist (from a previous MODE SELECT command SP parameter).

 

• Default values if pages have never been saved.

 

The drives generate a Unit Attention condition for all initiators (except for the one that was the

 

source of the MODE SELECT command) whenever one initiator modifies the Mode parameters.

Default

The default mode page set contains the factory default values that are listed in each page’s descrip-

tion.

 

Saved

The saved mode page set contains values preserved in the drive’s non-volatile memory by a pre-

vious SP-modified MODE SELECT command.

 

Changeable

The changeable mode page set provides a means for an initiator to determine which pages it is

allowed to change and the specific bits within those pages that it is allowed to change. This page

 

set is read-only and is fetched with a MODE SENSE command.

5.12.3Mode Parameter List

Table 5-51shows the format of the Mode Parameter List that is passed by the initiator to the drive during the command’s data-out buffer transfer. Table 5-52describes the fields. Table 5-53and Table 5-54provides a description of the data format and fields of the Mode Parameter Header. Table 5-55and Table 5-56describe the format and field descriptions for the Mode Parameter Block Descriptor.

Table 5-51Mode Parameter List-Data Format

Bit

7

6

5

4

 

3

2

1

0

Byte

 

 

 

 

 

 

 

 

 

 

0 – 3

 

 

 

Mode Parameter Header

 

 

 

 

 

 

 

 

 

 

 

4 – 11

 

 

 

Block Descriptor

 

 

 

 

 

 

 

(optional)

 

 

 

 

 

 

 

 

 

 

 

4 – n

 

 

 

 

Page(s)

 

 

 

or

 

 

 

 

 

 

 

 

 

 

 

(optional)

 

 

 

12 – n

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5-36 Maxtor Atlas 10K V