Fujitsu MHY2040BS Manuale Utente

In this situation, a part of read requested data including the top sector is stored in 
the data buffer. A transfer of the read requested data starts from the address where 
the data that is hit is stored until the top sector of the read requested data. 
Remaining part of insufficient data is read then. 

An example is a case where a partial hit occurs in cache data, as shown below. 

Cache valid data

START LBA

LAST LBA

 

1)  HAP is set at the address where partial hit data is stored, and Transfer is 

started. 

 

Cache valid data 

Partial hit data 

HAP (host address pointer) 

 

    

 

2)  DAP and HAP are set at the head of Buffer newly allocated, and insufficient 

data is read. 

 

Read segment 

HAP (host address pointer)

  

      

DAP (disk address pointer) 

 

3)  When reading the read requested data ends and the transmission of the read 

requested data to the host system ends, the read-ahead operation continues 
until a certain amount of data is stored. 

The method of storing the read-ahead data at Partial hit is the same as the 
Miss hit.  

Cache valid data

START LBA

LAST LBA

 

C141-E269 

6-19