  Symbol-pair codes are proposed to combat pair-errors in symbol-pair read
channels. The minimum symbol-pair distance is of significance in determining
the error-correcting capability of a symbol-pair code. Maximum distance
separable (MDS) symbol-pair codes are optimal in the sense that such codes can
achieve the Singleton bound. In this paper, two new classes of MDS symbol-pair
codes are proposed utilizing repeated-root cyclic codes over finite fields with
odd characteristic. Precisely, these codes poss minimum symbol-pair distance
ten or twelve, which is bigger than all the known MDS symbol-pair codes from
constacyclic codes.
