Data encoding in solid state storage devices

摘要

Methods and apparatus are provided for encoding input data for recording in s-level storage of a solid state storage device, where s f 2. Input data words are encoded in groups of M input data words in accordance with first and second BCH codes to produce, for each group, a set of M first codewords of the first BCH code. The set of M first codewords is produced such that at least one predetermined linear combination of the M first codewords produces a second codeword of the second BCH code, this second BCH code being a sub-code of the first BCH code. The sets of M first codewords are then recorded in the s-level storage. If each of the first and second codewords comprises N q-ary symbols where q=pk, k is a positive integer and p is a prime number, the q-ary code alphabet can be matched to the s-ary storage by ensuring that q and s are uth and vth powers respectively of a common base r, where u and v are positive integers and k f u, whereby p(k/u)v=s.

主权项

1. A method for recording input data in s-level storage of a solid state storage device, where s f 2, the method comprising:
encoding, by a processor, input data words in groups of M input data words in accordance with first and second BCH codes to produce, for each group, a set of M first codewords of the first BCH code such that a predetermined linear combination of the M first codewords produces a second codeword of the second BCH code, wherein the second BCH code is a sub-code of the first BCH code; recording the sets of M first codewords in the s-level storage; wherein each of the first and second codewords comprises N q-ary symbols where q=pk, k is a positive integer and p is a prime number; and q and s are uth and vth powers respectively of a common base r, where u and v are positive integers and k f u, whereby p(k/u)v=s; converting each q-ary first codeword into an r-ary first codeword prior to recording in the s-level storage; and mapping successive sets of v r-ary symbols of each r-ary first codeword to respective corresponding levels of the s-level storage in accordance with a predetermined mapping scheme, and recording each set of v r-ary symbols as said corresponding level in the s-level storage, wherein s ! q and r ! s.