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(3)
Full hit (hit all)
All requested data are stored in the data buffer. The disk drive starts transferring the requested
data from the address of which the requested data is stored. After completion of command, a
previously existed cache data before the full hit reading are still kept in the buffer, and the disk
drive does not perform the read-ahead operation. If the disk drive receives a full hit command
while performing the read-ahead operation, the disk drive starts transferring the requested data
without stopping the read-ahead operation.
1) In the case that the contents of the data buffer is as follows for example and the previous
command is a sequential read command, the disk drive sets the HAP to the address of which
the hit data is stored.
Last position at previous read command
HAP
Cache data
2) The disk drive transfers the requested data but does not perform the read-ahead operation.
Cache data
(4)
Partially hit
A part of requested data including a lead sector are stored in the data buffer. The disk drive
starts the data transfer from the address of the hit data corresponding to the lead sector of the
requested data, and reads remaining requested data from the disk media directly.
Following is an example of partially hit to the cache data.
Start LBA
6 - 18
HAP (set to hit position for data transfer)
Full hit data
Last position at previous read command
Full hit data
Cache data
C141-E106-01EN
Cache data
HAP
(stopped)
Cache data
Last LBA
DAP
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