FUJITSU MPB3052AT - Manual (Page 175)

C141-E045-02EN 6 - 20
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.
HAP (set to hit position for data transfer)
Last position at previous read command
Last position at previous read command
Cache data Full hit data Cache data
2) The disk drive transfers the requested data but does not perform the read-ahead operation.
(stopped)
HAP
Cache data Full hit data Cache data
3) The cache data for next read command is as follows.
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. The disk
drive does not perform the read-ahead operation after data transfer.
Following is an example of partially hit to the cache data.
Last LBA
Cache data
DAP
HAP
Last LBA Start LBA
Start LBA