Fujitsu MHN2100AT, MHN2150AT, MHN2300AT, MHN2200AT manual Sequential read

6.4 Read-Ahead Cache

3)After reading the requested data and transferring the requested data to the host system had been completed, the disk drive stops command execution without performing the read-ahead operation.

HAP (stopped)

Read-requested data Empty area

(stopped)

DAP

4) Following shows the cache enabled data for next read command.

	Cache enabled data		Empty area
Start LBA		Last LBA

6.4.3.2 Sequential read

When the disk drive receives the read command that targets the sequential address to the previous read command, the disk drive starts the read-ahead operation.

a.Sequential command just after non-sequential command

When the previously executed read command is an non-sequential command and the last sector address of the previous read command is sequential to the lead sector address of the received read command, the disk drive assumes the received command is a sequential command and performs the read-ahead operation after reading the requested data.

1)At receiving the sequential read command, the disk drive sets the DAP and HAP to the start address of the segment and reads the requested data from the load of the segment.

HAP

Mis-hit data Empty area

DAP

C141-E120-02EN 6-15