An apparatus according to an embodiment comprises a first storage, a second storage, an input unit, a shift number determining unit, and an output unit. The first storage stores identification information of sectors and defective information indicating a presence of defect on the data line, while associating the identification information and the defective information. The second storage has storage regions in a number larger than the first number. The input unit inputs data to the second storage by the first number at a time. The shift number determining unit determines a shift number. The output unit outputs the data stored in the storage regions which is after a head storage region by the shift number, as the data is to be supplied to the data line having no defect sector based upon the defective information, and outputs information that differs from the data to the defective data line.