Hitachi Ultrastar 15K73 Reference Manual page 140

OEM MANUAL:K6602924
Caching Page is specified to control look ahead caching.
A IC(Initiator Control) bit of one indicates that controller use the number of cache
segments or cache segment size fields, dependent upon the SIZE bit, to control the
caching algorithm rather than the controller own adaptive algorithm.
Since the controller does not support IC bit, this bit is ignored.
A CAP(Caching Analysis Permitted) bit of one indicates that the controller
perform caching analysis during subsequent operations. When zero, CAP requests
that caching analysis be disabled to reduce overhead time or to prevent
nonpertinent operations from impacting tuning values.
Since the controller does not support CAP bit, this bit is ignore.
A DISC(Discontinuity) bit of one indicates that the controller continue the pre-
fetch across time discontinuities (such as across cylinders, up to the limit of the
segment, space available for the pre-fetch).
A DISC bit of zero indicates that the controller truncates the pre-fetches at time
discontinuities.
Since the controller does not support DISC bit, this bit is ignored.
A SIZE(Size Enable) bit of one indicates that the Cache Segment Size is to be used
to control caching segmentation.
A SIZE bit of zero indicates that the Number of Cache Segments is to be used to
control caching segmentation.
WCE (Write Cable Enable) bit specifies the timing to inform the GOOD status for
WRITE command.
A WCE bit of one indicates that the controller may return GOOD status after
successfully storing all of the data in the cache before having successfully written
them the media.
A WCE bit of zero indicates that the controller returns GOOD status after all of
data has been written to the media.
MF (Multiplication Factor) bit specifies the interpretation of the minimum and
maximum Pre-fetch field.
A MF bit of zero indicates that the controller shall interpret these fields in terms of
the number of logical blocks for the pre-fetch.
A MF bit of one indicates that the controller shall interpret these fields in terms of
a scalar number which, when multiplied by the number of logical blocks to be
transferred (transfer length) for the current command, yields the number of logical
blocks for the pre-fetch.
Since the controller does not support MF bit, there should be 0 .
H
MODE SELECT:(15h)
5 COMMAND DESCRIPTIONS
Revision: 1 / Date: 2003.03.06
Page: 140 / 273