Table 5-69 Caching Page-Field Descriptions - Maxtor ATLAS 10K IV User Manual

Table 5-69
Default
Field
Value
PS 1
WCE 1
MF 0
RCD 0
Demand Read Re-
tention 0
Priority
Demand Write Re-
tention
0
Priority
Disable
FFFFh
Pre-Fetch Transfer
Length
Minimum
0
Pre-fetch
Maximum
0x7F5
Pre-fetch
Maximum
Pre-fetch 0x7F5
Ceiling
FSW 0
LBCSS 0
DRA 0
Caching Page - Field Descriptions
Parameters Savable. This bit is only used with the MODE SENSE command. A
returned value of 1 indicates that the target is capable of saving the page in a
non-volatile, vendor-specific location. Bit reserved with MODE SELECT com-
mand.
Write Cache Enable. The default value of 1 enables write-back caching when
processing a WRITE command. When set to 0 the drive returns a GOOD status
and COMMAND COMPLETE only after successfully writing all the data to the
media.
When WCE = 1, write-back caching is enabled while processing a WRITE com-
mand. The drive returns a GOOD status and COMMAND COMPLETE only af-
ter fetching the data from the initiator and placing it in the drive's cache
memory.
Note: For maximum data integrity, it is strongly recommended that when WCE
is set to 1, the Read-Write Error Recovery Page (01h) fields be set as follows:
• AWRE to 1
• RC to 0
• DCR to 0
• Correction Span set to 170
• Head Offset to 0
• Servo Offset to 0
Multiplication Factor (value must be 0). The drive interprets the minimum and
maximum pre-fetch fields values in terms of the number of logical blocks for
each of the respective types of prefetch.
Read Cache Disable. The default value of 0 enables the read cache capability
and allows the drive to use cache-resident data or medium data to satisfy a
READ command.
When the value is 1, read caching is disabled and the data returned in response
to a READ command is fetched from the medium and not from the drive's cache
memory.
This field advises the drive on the retention priority to assign data read into the
cache that has also been transferred from the drive to the initiator. Not supported
by the drive.
This field advises the drive on the retention priority to assign data written into
the cache that has also been transferred from the cache memory to the medium.
Not supported by the drive.
This field specifies the selective disabling of anticipatory pre-fetch
on long transfer lengths. The value in this field is compared to the number of
sectors requested by the current READ command. If the number of sectors is
greater the than the value specified, anticipatory pre-fetch is not performed for
the command. When 0, anticipatory pre-fetch is disabled. Ignored by the drive.
This field indicates the number of sectors that are to be pre-fetched. See also
MF.
This field indicates the maximum amount of data to pre-fetch into the cache as
a result of one READ command. Not supported by the drive.
Specifies an upper limit on the number of logical blocks computed as the max-
imum pre-fetch. If this number of sectors is greater than the maximum pre-
fetch, then the number of logical blocks to pre-fetch is reduced to the value
stored in the maximum pre-fetch ceiling field. Not supported by the drive.
The Force Sequential Write bit. Not supported by the drive.
The Logical Block Cache Segment Size bit. Not supported by the drive.
The Disable Read-Ahead bit. Not supported by the drive.
Description
Maxtor Atlas 10K IV
SCSI Description
5-47