Redundant recording disk device and data processing method using plural logical disks with mirrored data stored with a predetermined phase-offset

A redundant recording disk device for writing and reading data to and from parallel tracks repeatedly passing through respective positions for conversion in a plurality of disks, comprising:

• a plurality of disks which are rotated in synchronization with each other;
• a plurality of recording heads respectively corresponding to said plurality of disks for writing and reading data to and from respective recording surfaces of said disks;
• and
• control means for controlling the positions of said recording heads on said recording surfaces and the writing and reading of the data,
• said control means carrying out, when arbitrary data is written, control such that mirrored data are written into positions on the same cylinder on said plurality of disks, on said different recording surfaces, and having a predetermined phase difference around respective rotation axes of said plurality of disks, while carrying out, when said written arbitrary data is read out, control such that the mirrored data which have been written into said different recording surfaces are read out in a parallel manner.