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Parameter Data Format
"1": This enables the write cache.
"0": This prohibits operation of the write cache function.
d.
SIZE (size enable)
"1": Divides the data buffer in accordance with the value specified for the
"0": Divides the data buffer in accordance with the value specified for the
This bit cannot be changed. The HDD disregards the specification in this bit
and operates according to the "Default" value (= "0").
e.
DISC (discontinuity)
"1": Even if a track switch occurs during Look-Ahead, the Look-Ahead
"0": Look-Ahead is terminated at the point where track switch occurs during
This bit cannot be changed. The HDD disregards the specification in this bit
and operates according to the "Default" value (= "1").
f.
IC (initiator control enable)
"1": Dividing of cache segments is according to the SIZE bit specification.
"0": Dividing of the cache segments is performed by an algorithm that is inherent
This bit can be changed, and its operation is as specified.
g.
Demand read retention priority (not supported)
This field advises the device server the retention priority to assign for data
read into the cache that has also been transferred from the logical unit to the
INIT.
The HDD are not supported this field. Thus, the HDD disregards the
specification in this field.
"F": Data put into the cache via a READ command was not replaced if there is
300
Write data remains in the buffer memory, the cache is made the object
even for a read command, and when all of the write data has been
received, "GOOD" status is reported without waiting for writing data to
the disk media.
Sequential writing is performed without waiting for rotation.
Write data remains in the buffer memory, the cache is not made the
object even for a read command, and as soon as all the data has been
written to the disk, "GOOD" status is reported.
cache segment size (bytes 14, 15).
number of cache segments (byte 13).
operation continues without interruption.
Look-Ahead.
in the HDD.
other data in the cache that was placed into the cache by other means and
it may be replaced.
C141-C013
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