US Patent 7174421 HDD with rapid availability of critical data after critical event

A hard drive retrieves critical data determined to be requested by a host device in the near future and stores it in cache. The hard drive provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. The critical data is retrieved upon the occurrence of a critical event. The critical data may be related to power-on of the computer, such as boot sector FAT system data. Thus, the cache of the present invention may use old data rather than new data or the last data accessed.