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6.Command Specification
6.7.2. Data Compression Control Page (0Fh)
The drive supports the Data Compression Control Page which has the following format:
Bit
7
Byte
0
PS (0)
1
2
DCE
3
DDE
4
(MSB)
7
8
(MSB)
11
12
13
14
15
Note: If the drive does not support compression the drive will return Check Condition status, and the sense key will
be set to ILLEGAL REQUEST.
This page specifies the parameters for the control of the data compression capability of the drive.
DCE: A Data Compression Enable (DCE) bit of one indicates that data compression is enabled. When this bit is set,
data sent to the device by the initiator shall be processed using the selected compression algorithm before being
written to the medium. A DCE bit of ZERO indicates that data compression is disabled.
DCC: A Data Compression Capable (DCC) bit of one indicates that the drive supports data compression and shall
process data sent to it for transferal to the medium using the selected compression algorithm when the DCE bit is
one. A DCC bit of ZERO indicates that the device does not support data compression. This shall be a
non-changeable field. The SDX-250V has the capability to decompress data and will set this bit to a one.
DDE: A Data Decompression Enable (DDE) bit of one indicates that data decompression is enabled. The SDX-250V
will always decompress the data. Setting this bit to ZERO has no effect.
RED: The Report Exception on Decompression (RED) field indicates the device's response to a boundary condition
caused by a change in the format of recorded data from:
uncompressed to compressed or compressed to uncompressed
This field only has an effect during reading not during writing. This field is not supported and should be always set to
00b.
6-30
Table 6-36: Data Compression Control Page
6
5
Reserved
DCC
RED
Compression Algorithm
Decompression Algorithm
4
3
Page Code (0Fh)
Page Length (0Eh)
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
SONY AIT-E Turbo drive SDX-250V series Ver.1.0
MODE SELECT
2
1
0
(LSB)
(LSB)
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