Fujitsu MPF3XXXAH manual HAP set to hit position for data transfer

(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 HAP (set to hit position for data transfer)

Cache data

Full hit data

Cache data

DAP

Last position at previous read command

2) The disk drive transfers the requested data but does not perform the read-ahead operation.

HAP (stopped)

Cache data

Full hit data

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.

Cache data

Start LBA Last LBA

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