Quantum Instruments DLT 7000 User Manual
Page 114
SCSI Commands
5-10
Quantum DLT 7000 Tape System
Table 5–5 DATA-Phase Command Contents (Continued)
Command
Length in CDB
Data Out (To
Drive)
Data In
(To Initiator)
REWIND
0
---
---
SEND DIAGNOSTIC
Parameter List
Diagnostic Page
---
SPACE
0
---
---
TEST UNIT READY
0
---
---
VERIFY
Transfer
Data
---
WRITE
Transfer
Data
---
WRITE BUFFER
Parameter List
Microcode Image
Data
---
WRITE FILEMARKS
---
---
---
5.1.5 Unit Attention Condition
Queued Unit Attentions are implemented on the Quantum DLT 7000 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.