Method and device for improving the reliability of data storage in a hard disk comprising a plurality of platters

A method for a controller of a hard disk including a plurality of platters, each platter including a data storage surface, the method including: obtaining data blocks, each block having to be or being stored on the hard disk, the number of blocks being less than that of surfaces of platters; calculating a redundancy data block based on each block, the number of redundancy data blocks added to the number of blocks being less than or equal to that of surfaces of platters; writing the redundancy data block on a platter surface, separate from the surfaces for storing each block; accessing data blocks corresponding to a data item to read from the hard disk and accessing a redundancy data block corresponding to the data item to read, each block accessed and each redundancy data block associated with the data item to read being accessed on a separate platter surface; and checking the integrity of the data item.