Host Interface
4.4.5 Cache function
The ODD supports the read cache and MO write cache.
The read cache consists of the read ahead cache and the LRU cache that reads write data remaining in the data buffer.
The read ahead cache allows for data transfer at a near effective transfer speed during continuous read operation without causing any delay owing to rotation latency. LRU allows for data transfer with no mechanical operation if write and read operations are executed frequently on the same sector.
The MO write cache writes data in batch mode during continuous write operation, thus reducing positioning operations depending on the buffer size and recovering the write throughput.
4.4.5.1 Data buffer
The ODD uses part of the buffer area as work memory for control firmware and the remaining area as a buffer. The data buffer consists of plural segments and contains write data of plural segments.
4.4.5.2 Read cache
The ODD enables the read ahead cache and LRU cache when the cache function is enabled. When the read cache is enabled, the ODD contiguously
When data in the sector specified by the host hits
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Processing for access to alternate sectors
Read error and retry processing
Media physical zone boundary
Read command reception for a sector that is not contiguous from the specified sector of the previous Read command operation
Full data buffer
Media ejection request issued using the eject switch
Hardware/software reset, DEVICE RESET command reception, or
