1. A method of providing combined error code protection and subgroup parity protection for a given group of n bits, the method comprising the steps of: identifying a number, m, of redundant bits for said error code protection; constructing an error correction code (ECC) checkbits generator matrix P for generating an ECC word for said given group of n bits and for generating parity bits for subgroups of said given group of n bits, wherein the matrix P includes a multitude of rows and columns, multiplying said given group of n bits with P produces m redundant error correction code protection bits, and two of the columns of P provide parity bits for parity protection for subgroups of said given group of n bits; and using a computer system, implementing a matrix construction algorithm, for performing the step of constructing the matrix P.