Abstract: A data input/output control apparatus and a storage device accessing method are provided wherein multiple information is simultaneously supplied to multiple users. Multiple information to be supplied to users is stored distributedly in a plurality of storage devices. A slot allocating unit determines the number S of slots such that the value S is prime to the number D of storage devices, and groups time zones in which data is read from or written into the storage devices to S slots in access order. On receiving an access demand from a user, the slot allocating unit allocates slots to the user. When writing data into a specific storage device, an access control unit writes data into the specific storage device by using a specific slot for accessing the specific storage device, from among the slots allocated to the user, and a slot which is D-1 slots before the specific slot. Consequently, a plurality of groups (dependence rings) of mutually dependent slots are formed.