an apparatus for controlling data transfer between a rotary storage device such as a magnetic disk having a plurality of heads for different tracks and another storage device such as a disk cache includes a plurality of transfer circuits for the purpose of simultaneous data transfer to and from a plurality of tracks . the transfer circuits operate concurrently with and independently of each other to transfer data therethrough and other than noting the regions to be skipped over , ignoring data format on the track . the apparatus is suitable for preloading a disk cache from a disk .