Disk cache unit having reduced waiting times for data transfer

摘要: A disk cache control unit disposed between an upper-rank processor and a unit, comprising memory for holding copy of data stored in the at least one first interface controller which checks, response to input/output command requesting be read from processor, whether or not requested by is memory, requests head positioning when second indicates request, notifies completion notice positioning, reads stores transfer request did come specified time period set without rotational delay after been given subsequent had completed, gives storage through means controller, this notice, transfers processor.