US Patent 7697816 Circulating memory apparatus and image storage distribution system

A circulating memory apparatus and a data storage and distribution system using a circulating recording area effectively and having an improved access efficiency to the circulating recording area are disclosed. A memory area secured in a disk unit is used in circulation thereby to record the time series input data. The time series input data are edited into a data block of a predetermined size including a plurality of subblocks, and written into the disk unit by data block. In response to a request for outputting specific data, the data are read by subblock from the disk unit into a cache memory thereby to selectively output the specific data contained in the subblocks.