Patent ID: 6898754

Claim:
A magnetic tape comprising multiple parallel diagonal tracks together storing (a) N data bytes divided into M sub groups, each of the subgroups having data bytes as well as C 1 and C 2 orthogonal redundancy coding bytes; and (b) a C 3 error correcting sub group resulting from the M sub groups; each of the sub groups having P bytes; each pair of the parallel diagonal tracks together including one of the sub groups so that a first track of each diagonal track pair includes P/2 bytes of sub group i and a second track of each diagonal track pair includes the remaining P/2 bytes of sub group i, where i =1 . . . M; the error correcting sub group being in an additional pair of the parallel diagonal tracks A and B; the bytes in tracks A and B having values resulting from byte k of the 2M tracks being combined; track j including a pair of further check bytes derived in accordance with the polynomial X 2 +Xα 2 +α, where α is the primitive element GF(2 8 ), X=the value of the byte k of track j, j=1 . . . 2M,A,B and k=1 . . . P/12.