Information recording and reproducing apparatus and a method of data caching including read-ahead capability

摘要

An information recording and reproducing apparatus according to the present invention includes a read-ahead history buffer which is used as a ring buffer. A read-ahead operation is performed, every time a reproduction request is made by a host device, so as to maintain the read-ahead data after the last block for which reproduction has been requested at a predetermined value. Data which has already been requested by the host device and has not been overwritten by the read-ahead operation is treated as history data. As a result, data centered around (i.e., preceding and following) the last block for which the host device has requested reproduction is always secured as cache data.