Using The Read Segment Buffer; Miss-Hit (No Hit - Fujitsu MHR2010AT Product Manual

Operations

6.4.3 Using the read segment buffer

Methods of using the read segment buffer are explained for the following
situations.

6.4.3.1 Miss-hit (no hit)

In this situations, the top block of read requested data is not stored at all in the
data buffer. As a result, all of the read requested data is read from disk media.
1) HAP (host address point) and DAP (disk address point) are defined in the
sequential address of the segment that is read last.
HAP (host address pointer)
DAP (disk address pointer)
2) During reading of read requested data, the request data that has already been
read is sent to the host system.
HAP
Read requested data
3) When reading of read requested data is completed and transfer of the read
requested data to the host system is completed, reading of the disk continues
until a certain amount of data is stored.
Read requested data
6-14
Read segment
Read requested data is
stored until this point.
DAP
HAP
(stop)
Free space
Read-ahead data
DAP
C141-E145-02EN
(stop)