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Mode sense 1ah/5ah, Pre-execution checks, Command descriptor block – HP Q153090901 User Manual

Page 96: Mode sense ah/5ah 96

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Commands

96

MODE SENSE

1Ah/5Ah

M

ODE SENSE

allows the drive to return its current configuration and report which configuration

parameters can be changed through

MODE SELECT.

The mode sense header, block descriptor (optional), and zero or more of the are sent to the host.

Mode pages contain drive configuration parameters. Some of these parameters are fixed, others

are configurable (through the

MODE SELECT

command). The host should use

MODE SENSE

to

determine which drive parameters are configurable and what their current values are before using

mode select to alter them.

NOTE:

See

MODE SELECT

on page 71 for full descriptions of the Mode Parameters.If a

MODE

SENSE

command is issued whilst an immediate reported Load command is executing or close

to completing then the values of some parameters in some mode pages which depend on the

results of the load may be undefined.

Similarly, the write-protect field in the Mode Parameter Header will be unstable unless a

cartridge is present and medium removal is prevented.

Pre-execution checks:

The page code field must contain a valid mode page code or the value 0 or the value 3Fh. If it

does not then

CHECK CONDITION

status is reported. Sense data will be as described in the Illegal

Field Checks.

Command descriptor block:

6-Byte Version

Illegal Field

Reservation

Deferred Error

Unit Attention

7

6

5

4

3

2

1

0

0

Operation Code (1Ah)

1

Reserved (0)

DBD

Reserved (0)

2

PC

Page Code

3

Sub Page Code

4

Allocation Length

5

Control