Quantum LTO 4, Руководство пользователя

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SCSI Commands: 49BTEST UNIT READY Page 214
3.37 TEST UNIT READY
The TEST UNIT READY command provides a means to check that the drive is
ready.
If the drive is able to accept a medium-access command without returning a Check
Condition status, then the TEST UNIT READY command will result in Good status.
If the drive is unable to become operational or is in a state that requires action from
the host to make the drive ready, then the TEST UNIT READY command will result
in a Check Condition status with a sense key of Not Ready.
This command does not access the medium or initiate a diagnostic routine.
3.37.1 TEST UNIT READY Command Descriptor Block
Byte Bits
7 6 5 4 3 2 1 0
0 Operation Code (00h)
1 Ignored LUN Reserved
2 Reserved
3 Reserved
4 Reserved
5 Control
3.37.1.1 TEST UNIT READY Command Field Descriptions
Field Bytes Bits Description
Operation
Code 0 The Operation Code for TEST UNIT READY is 00h.
Ignored
Logical
Unit 1 5-7 The LUN field is vestigial from the SCSI-1 standard and is ignored.
Reserved All reserved bits must be 0.
Control 5 The control field must be 0.
3.37.2 TEST UNIT READY Completion Status
Code Message Description
00h Good
Status
•
The drive is ready to perform any appropriate medium access command.
•
The drive remains in any previously set mode.
•
The tape is not moved.
02h Check
Condition Use the REQUEST SENSE command to retrieve the sense data.
Code Message Description
02h Not Ready No cartridge is present; an immediate command
is in progress; or the eject button has been
pressed.
04h Hardware Error Parity error on the SCSI bus or drive hardware
failure.
05h Illegal Request The Command Descriptor Block is invalid.
06h Unit Attention The cartridge was changed or the drive was reset.