A computer-implemented method for writing data to a sequential storage medium, includes: writing plural data blocks sequentially to the sequential storage medium; and writing a data pattern to an area on the sequential storage medium, the area being an area to which none of the plural data blocks is written, the data pattern including plural bit patterns appearing in none of the plural data blocks, and thus representing that none of the plural data blocks is written to the area and representing specific information regarding the sequential storage medium.