Sequential Hit; Full Hit - Fujitsu MHV2120BH Product Manual

6.4.3.2 Sequential hit

When the read command that is targeted at a sequential address is received after
execution of the read commands is completed, the read command transmits the
Read requested data to the host system continuing read-ahead without newly
allocating the buffer for read.
1) When the sequential read command is received, HAP is set in the sequential
address of the last read command, and DAP is set at a present read position as
it is.
Cache valid data
2) During reading of read requested data, the request data that has already been
read is sent to the host system.
Cache valid data
3) When reading of read requested data is completed and transfer of the read
requested data to the host system is completed, the read-ahead operation
continues until a certain amount of data is stored.
Cache valid data
4) The following cache valid data is for the read command that is executed next:

6.4.3.3 Full hit

In this situation, all read requested data is stored in the data buffer. Transfer of
the read requested data is started from the location where hit data is stored. For
C141-E224
HAP (host address pointer)
Read requested data
Read-ahead data
HAP (host address pointer)
Read requested data
Read requested data
Cache valid data
LAST LBA START LBA
6.4 Read-ahead Cache
Free space
DAP (disk address pointer)
Free space
DAP (disk address pointer)
HAP (host address pointer)
Read-ahead
Read-ahead
data data
DAP (disk address pointer)
Free
space
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