MODE SENSE 1Ah/5Ah
Commands
97
10-byte version
CDB fields:
7 6 5 4 3 2 1 0
0 Operation Code (5Ah)
1 Reserved (0) DBD Reserved (0)
2 PC Page Code
3 Sub Page Code
4
Reserved (0)
6
7 (MSB)
Allocation Length
8 (LSB)
9 Control
DBD Disable Block Descriptors flag
0 Allows the drive to return the
MODE SELECT block descriptor.
1 Prevents the drive from returning the
MODE SELECT block descriptor.
PC Page Control—Indicates the type of page parameter values to be returned to the host, as
shown in the following table:
7 6 Description
00Report Current Values: the current values of the parameters are returned.
01Report Changeable Values: the page returned has its non-changeable
parameter fields cleared to 0. The fields that are changeable are set to all
1’s.
10/1Report Default Values: the page returned contains the power-on/reset/bus-
device-reset values of the mode parameters.
Page Code This allows the host to select any specific page, or all the pages supported by the drive.
0 The drive returns no mode pages, so only the header and block descriptor
are returned.
Any mode
page code
The drive returns that page.
3Fh The drive returns all mode pages.
Sub Page
Code
The sub-page code of the page code for data to be returned. If there are no sub-pages, it
should be set to 0.
Allocation
Length
Specifies the number of bytes that the host has allocated for returned MODE SENSE data.
0 No data transfer will occur. This is not considered an error.
n The maximum number of bytes which the drive should return in its data-out phase.
Either the entire mode page or allocation length bytes of the page are returned,
whichever is least.
