Unit Attention Condition - Quantum DLT 8000 Product Manual

SCSI Commands
Table 5–5 DATA-Phase Command Contents (continued)
Command
REPORT LUNS
REQUEST SENSE
RESERVE UNIT
REWIND
SEND DIAGNOSTIC
SPACE
TEST UNIT READY
VERIFY
WRITE
WRITE BUFFER
WRITE FILEMARKS

5.1.5 Unit Attention Condition

Queued Unit Attentions are implemented on the Quantum DLT 8000 tape drive and are
maintained separately for each valid LUN for each initiator. Unit Attentions are created
in each of the following circumstances:
At Power On
At Bus Reset
At Bus Device Reset message
When the medium may have changed asynchronously
When another initiator changes the Mode Parameters
When a firmware (microcode) update has completed
Two queued Unit Attentions are not unusual. For example, if a unit is powered up and a
tape cartridge is loaded, Power Up and Not-Ready to Ready Transition Unit Attentions
are created. Due to the limited number of Unit Attention buffers, if an initiator does not
clear Unit Attentions queued for it, at some point the tape drive stops generating new
Unit Attentions for that initiator-logical unit combination (existing ones will be left
queued, however).
A LOAD command does not generate a Unit Attention for the initiator that issued the
command since the transition to Ready is synchronous.
5-10
Length in CDB
Allocation
Allocation
0
(Extent List Option
not supported)
0
Parameter List
0
0
Transfer
Transfer
Parameter List
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Quantum DLT 8000 Tape System
Data Out
(To Drive)
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Diagnostic Page
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Data
Data
Microcode Image Data
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Data In
(To Initiator)
Supported LUNS List
Sense Data (18)
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