Fujitsu MHA2021AT Product Manual page 159

Operations
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
DAP
2) The disk drive transfers the requested data that is already read to the host
system with reading the requested data.
HAP
Requested data
3) After completion of the reading and transferring the requested data to the host
system, the disk drive performs the read-ahead operation continuously.
Requested data
4) The disk drive performs the read-ahead operation for all area of segment with
overwriting the requested data. Finally, the cache data in the buffer is as
follows.
6-18
Mis-hit data
DAP
HAP (Completion of transferring requested data)
HAP
Read-ahead data
DAP
Last LBA Start LBA
Empty area
Empty area
Empty area
Read-ahead data
DAP
C141-E042-01EN