Usage Of Read Segment - Fujitsu MPG3xxxAT Product Manual

6.5.3

Usage of read segment

This subsection explains the usage of the read segment buffer at following cases.
(1) Miss-hit (no hit)
A lead block of the read-requested data is not stored in the data buffer. The requested data is read
from the disk media.
1) Sets the host address pointer (HAP) and the disk address pointer (DAP) to the sequential
address to the last read segment.
HAP
DAP
2) Transfers the requested data that already read to the host system with reading the requested
data from the disk media.
HAP
Read-requested data
3) After reading the requested data and transferring the requested data to the host system had
been completed, the disk drive continues to read till a certain amount of data is stored.
Read-requested data
4) Following shows the cache enabled data for next read command.
Start LBA
Segment for read
Stores the read-requested
data upto this point
DAP
HAP
Cache enabled data
C141-E110-02EN
Empty area
(stopped)
Read Ahead Data
(stopped)
DAP
Last LBA
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