Request Sense Command; Sense Data Management - Quantum LTO 2 User Manual

REQUEST SENSE Command

Sense Data Management

LTO-2 SCSI Interface Guide
The
REQUEST SENSE
Sense Data is updated with each command; therefore, the sense data only
reports the status of the immediately previous command. If a Check
Condition status results, a
to recover the information form the Sense Data.
The
REQUEST SENSE
fatal error occurs during execution of the
nonfatal errors occur during the
is returned. Sense Data may be invalid following a fatal error on a
REQUEST SENSE
The drive maintains three types of sense data.
2
•
Current Sense
received from the initiator.
•
Deferred Sense
as good, but has generated sense data after being reported. This may
be a command with the Immediate flag set or may be a buffered
write. A command with the Immediate flag set will generate sense for
the host that sent the command. A buffered write will generate sense
for all hosts.
•
Unit Attention Sense
condition. This is generated for all hosts.
Any command other than a
command will generate Check Condition status if there is Deferred Sense
data or Unit Attention data available. All commands will generate Check
Condition status if the command itself generates sense data. If the next
command after the Check Condition status is not a
command, then all the sense data for that initiator is cleared.
When a
REQUEST SENSE
returned. If there is no Current Sense, the Deferred Sense is returned. If
there is no Deferred Sense, the Unit Attention Sense is returned. If there is
no Unit Attention Sense, default sense data is returned. Once a particular
set of sense data has been returned, that sense data is cleared. Any other
command returns the status of the last command.
REQUEST SENSE
command returns Check Condition status only if a
REQUEST SENSE
command.
is sense data associated with the last command
is sense data from a command that has been reported
is sense data generated by a Unit Attention
REQUEST SENSE
command is received, the Current Sense is
Chapter 2 SCSI Commands
REQUEST SENSE Command
command should be issued
command. If
REQUEST SENSE
execution, Good Status
command or an
REQUEST SENSE
2
INQUIRY
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