Fujitsu MHD2032AT, MHC2032AT, MHD2021AT, MHC2040AT manual Full hit hit all

Operations

4)Finally, the cache data in the buffer is as follows.

Read-ahead data

Start LBA Last LBA

c.Non-sequential command immediately after sequential command

When a sequential read command (first read) has been executed, the first read operation should be stopped if a non-sequential read command has been received and then, ten or more of the non-sequential read commands have been received. (Refer to 6.5.3.1.)

The figure that describes the first read operation is the same as that shown in the sub-section a.

6.5.3.3Full 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.

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

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