Page
112
LTO SCSI Interface Manual
SET CAPACITY
The Set Capacity command sets the available medium for a volume to a proportion
of the total capacity of that volume. Any excess space is unavailable on the volume
after successful completion of this command until reset by a new Set Capacity
command.
The Set Capacity command is valid only when the medium is at beginning-of-
medium. If the medium is logically at any other position, the command is rejected
with Check Condition status. The sense key is Illegal Request with the additional
sense code and an additional sense code qualifier set to position past beginning of
medium.
If the medium is write protected, the command is rejected with Check Condition
status. The sense key is Data Protect with the additional sense code and an
additional sense code qualifier set to Write Protected.
If the Set Capacity command specifies the portion of the total volume capacity to be
made available for use less than 10 gigabytes, the device will round up the capacity
to 10 gigabytes. The command is terminated with Check Condition status. The sense
key is Recovered Error with the additional sense code and an additional sense code
qualifier set to Rounded Parameter.
A valid Set Capacity command causes all data on the tape to be lost.
Command Descriptor Block
Byte
Bits
7
6
5
4
3
2
1
0
0
Operation Code (0Bh)
1
Ignored LUN Reserved
Immed
2
Reserved
3
Capacity Proportion Value, MSB
4
Capacity Proportion Value, LSB
5
Control
Field Descriptions
Field
Bytes
Bits
Description
Operation
Code
0
The Operation Code for Set Capacity is 0Bh.
Ignored
Logical
Unit
1
5-7
The LUN field is residual from the SCSI-1 days and is ignored.
Immed
1
0
0 = Status is not returned until the operation is complete
1 = Status is returned as soon as the operation is initiated.
Capacity
Proportion
Value
3-4
This field specifies the portion of the total tape capacity to be made
available for use. The Capacity Proportion Value is the numerator of
a fraction with a denominator of 65535. The resulting available tape
capacity is equal to the total tape capacity multiplied by this fraction.
The drive rounds up the capacity to the next higher supported value.
Reserved
All reserved bits must be 0.
Control
5
See Control Byte Format on page 18.
