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Current sense, Unit attention sense, Clearing current sense – HP C737990900 User Manual

Page 132

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132 Commands

D

EFERRED ERROR

sense

Unless otherwise stated, all the following descriptions apply to the sense data

for a single host whose command is being executed.

Current Sense

Current sense is the data that is returned in response to a

REQUEST SENSE

command. It is modified or updated in the following circumstances:

It is cleared in response to the arrival of any command other than

REQUEST

SENSE

or

INQUIRY

.

It is cleared following execution of a

REQUEST SENSE

command.

If the current command fails, sense is set according to the failure and

CHECK CONDITION

is reported to the host that sent the command.

If the previous command terminated with an unexpected

BUS FREE

, current

sense is set according to the reason for the bus release.

If the command fails its pre-execution check for Unit Attention,

UNIT

ATTENTION

sense is copied to the Current sense, and

CHECK CONDITION

is

reported to the host that sent the command.

If the command fails its pre-execution check for Deferred Error,

DEFERRED

ERROR

sense is copied to the Current sense, and

CHECK CONDITION

is

reported to the host that sent the command.

Clearing Current Sense:

Clearing the Current sense involves setting sense fields as follows:

Valid = 0

error code = 0x70

segment number = 0

ILI = 0

sense key = 0

information bytes = 0

command specific information = 0

fru code = 0

SKSV = 0

UNIT ATTENTION Sense

U

NIT ATTENTION

sense is set when one of the following Unit Attention

conditions occur: