1. A data recording and reproduction apparatus comprising: a recording/reproduction controller that controls recording and reproduction of information; a request classifier that classifies each request from the recording/reproduction controller into any one of a real-time processing data request, a metadata request, and a non-real-time data request; an input/output request accumulator that sequentially accumulates each classified input/output request; an input/output request readout device that, when any input/output requests are accumulated in the input/output request accumulator, sequentially reads out each accumulated input/output request in accordance with a predetermined reference time; and an input/output execution unit that, in response to each input/output request read by the input/output request readout device, executes input/output processing with respect to a storage medium, wherein, in order to attain a desired data rate of the real-time processing data, the input/output request readout device delays reading out a metadata input/output request for a fixed period specified by the reference time and collectively executes processing of a delayed metadata input/output request with a subsequent metadata input/output request.