Fujitsu MHT2030AT Manual/User Guide - Page 237

6.4 Read-ahead Cache 4) The following cache valid data is for the read command that is executed next: Cache valid data LAST LBA START LBA 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 data that is a target of caching and remains before a full hit, the data is retained when execution of the command is completed. This is done so that a new readahead operation is not performed. If the full hit command is received during the read-ahead operation, a transfer of the read requested data starts while the readahead operation is in progress. 1) An example is the state shown below where the previous read command is executing sequential reading. First, HAP is set at the location where hit data is stored. HAP end location of the previous read command HAP HAP (It is reset to the hit data location for transfers.) Cache data Full hit data Cache data DAP DAP end location of the previous read command 2) The read requested data is transferred, and a new read-ahead operation is not performed. Cache data Full hit data HAP (stop) Cache data C141-E192-02EN 6-17