Control apparatus, method of controlling apparatus and computer-readable recording medium

A control apparatus connectable to a memory unit for storing data, for controlling a first tape writing unit including a plurality of first tapes and a second tape writing unit including a plurality of second tapes so that the first and second writing units write same data stored in the memory unit to one of the first tapes and one of the second tapes, respectively, has an obtaining unit for obtaining a progress value indicating a progress of writing data into the one of the second tapes upon completely writing the data into one of the first tapes and a controller for controlling the first and the second tape writing units so that the first and the second writing unit change the writing tapes to another of the first tapes and another of second tapes when the progress value being not more than a predetermined value.