Fujitsu MBB2073RC Computer Drive User Manual


 
5.1 Mode Parameters
"1": Data put into the cache via a READ command was replaced sooner than
data placed into the cache by other means.
"0": Indicates the device server was not distinguish between retaining the
indicated data and data placed into the cache memory by other means.
h. Write retention priority (not supported)
This field advises the device server the retention priority to assign for data
written into the cache that has also been transferred from the cache memory to
the medium.
The HDD are not supported this field. Thus, the HDD disregards the
specification in this field.
"F": Data put into the cache during a WRITE or WRITE AND VERIFY
command was not replaced if there is other data in the cache that was
placed into the cache by other means and it may be replaced.
"1": Data put into the cache during a WRITE or WRITE AND VERIFY
command was replaced sooner than data placed into the cache by other
means.
"0": Indicates the device server was not distinguish between retaining the
indicated data and data placed into the cache memory by other means.
i. Disable pre-fetch transfer length
This parameter is used to selectively prohibit data Look-Ahead operations in
the READ command or the READ EXTENDED command. When the
"Transfer block count" specified in the CDB of the READ command or the
READ EXTENDED command is greater than the value in this parameter, data
Look-Ahead operations are not executed in that command. This bit cannot be
changed. The HDD disregards the specification in this bit and operates
according to the "Default" value (= X 'FFFF').
j. Minimum pre-fetch (not supported)
This parameter specifies the minimum quantity of logical data blocks pre-
fetched to the data buffer with the READ command or READ EXTENDED
command.
This parameter cannot be changed. The HDD disregards the specification in
this field.
k. Maximum pre-fetch (not supported)
This parameter specifies the maximum quantity of logical data blocks pre-
fetched to the data buffer with the READ command or READ EXTENDED
command.
The HDD varies the pre-fetch volume according to the volume of data
requested by the READ command or READ EXTENDED command. The
value reported to the MODE SENSE command always indicates the number
of blocks corresponding to 1 cache segment – 1.
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