Fujitsu MPE3064AT, Product Manual

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C141-E077-01EN 6 - 17
b. Sequential hit
When the last sector address of the previous read command is sequential to the lead sector
address of the received read command, the disk drive transfers the hit data in the buffer to
the host system.
The disk drive performs the read-ahead operation of the new continuous data to the empty
area that becomes vacant by data transfer at the same time as the disk drive starts
transferring data to the host system.
1) In the case that the contents of buffer is as follows at receiving a read command;
Start LBA Last LBA
DAP
HAP (Completion of transferring requested data)
Hit data Read-ahead data
2) The disk drive starts the read-ahead operation to the empty area that becomes vacant
by data transfer at the same time as the disk drive starts transferring hit data.
DAP
HAP
Hit data New read-ahead data Read-ahead data
3) After completion of data transfer of hit data, the disk drive performs the read-ahead
operation for the data area of which the disk drive transferred hit data.
Read-ahead data
DAP
HAP