Methods and apparatus for implementing run-length limited and maximum transition run codes

An apparatus for encoding information, the apparatus comprising:

• an encoder for converting data words into corresponding codewords of a code, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, and a set of the data words is partitioned into a plurality of disjoint subsets each including one or more of the data words and corresponding to a distinct mapping, and further wherein the encoder converts a given data word by applying to that data word the mapping associated with the subset containing that data word.

A method of decoding information, the method comprising the steps of:

• converting codewords of a code into corresponding data words, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, and a set of the codewords is partitioned into a plurality of disjoint subsets each including one or more of the codewords and corresponding to a distinct mapping, and further wherein the converting step includes applying to a given codeword the mapping associated with the subset containing that codeword;
• and
• outputting the data words.

An apparatus for decoding information, the apparatus comprising:

• a decoder for converting codewords of a code into corresponding data words, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, and a set of the codewords is partitioned into a plurality of disjoint subsets each including one or more of the codewords and corresponding to a distinct mapping, and further wherein the converting step includes applying to a given codeword the mapping associated with the subset containing that codeword.

A method of encoding information, the method comprising the steps of:

• converting data words into corresponding codewords of a code, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, and the data words are partitioned into a plurality of disjoint subsets each corresponding to a distinct mapping, wherein the converting step includes applying to a given data word the mapping associated with the subset containing that data word, and further wherein if Y=ψ(X) represents the mapping of a given data word X onto a corresponding codeword Y, then X′ and Y′ representing the words X and Y in reversed order, satisfy the relation Y′=ψ(X′);
• and
• outputting the codewords.

A method of encoding information, the method comprising the steps of:

• converting data words into corresponding codewords of a code, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, the one or more constraints comprising one of an F={1111, 11100} NRZI strong constraint, an F={1111, 00111} NRZI strong constraint, an F={1111, 11100odd, 00111odd} NRZI strong constraint, an F={1111} NRZI weak constraint, an F={11111} NRZI weak constraint, and an F={1010} NRZ weak constraint, and the data words are partitioned into a plurality of disjoint subsets each corresponding to a distinct mapping, and further wherein the converting step includes applying to a given data word the mapping associated with the subset containing that data word;
• and
• outputting the codewords.

A method of encoding information, the method comprising the steps of:

• converting data words into corresponding codewords of a code, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, and the data words are partitioned into a plurality of disjoint subsets each corresponding to a distinct mapping, wherein the code is a rate 16/17, (0,3,2,2) MTR code which satisfies a (0,15,9,9) RLL constraint, and further wherein the code is equivalent to a rate 16/17, (0,3,2,2) RLL code which satisfies a (0,15,9,9) MTR constraint and in which the ones and zeros are interchanged, and further wherein the converting step includes applying to a given data word the mapping associated with the subset containing that data word;
• and
• outputting the codewords.

A method of encoding information, the method comprising the steps of:

• converting data words into corresponding codewords of a code, wherein the code is generated by interleaving symbols of a first code with uncoded bits of a data word, wherein the codewords are subject to one or more constraints on the number of consecutive like symbols, and wherein the data words are partitioned into a plurality of disjoint subsets each corresponding to a distinct mapping, and further wherein the converting step includes applying to a given data word the mapping associated with the subset containing that data word;
• and
• outputting the codewords.