a technique for recovering of “ squeezed ” sectors in a set of sequential sectors such as are used in shingled magnetic recording is described . embodiments of the invention use a programmable erased sector recovery scheme , which is a concatenation of a “ cauchy - type ” track erasure correction code , together with a media - error correction code that generates n - weighted parity - sectors per track and is capable of replacing up to n - erased sectors per track in any possible combination .