Segregation of redundant control bits in an ECC permuted, systematic modulation code

An encoder, comprising:

• a modulation encoder for:
• receiving a plurality of user information from an arbitrated sector buffer implemented within a hard disk drive (HDD);
• and
• encoding first user information of the plurality of user information thereby generating first scrambled user information and first modulation redundancy bits;
• encoding second user information of the plurality of user information thereby generating second scrambled user information and second modulation redundancy bits;
• and
• outputting a modulation encoded codeword that includes the first scrambled user information, followed by the second scrambled user information, followed by the first modulation redundancy bits, followed by the second modulation redundancy bits;
• and
• a RS (Reed-Solomon) encoder for encoding the modulation encoded codeword thereby generating a RS codeword that includes RS redundancy bits;
• and wherein:
• the first scrambled user information and the second scrambled user information forming scrambled user information;
• the first modulation redundancy bits and the second modulation redundancy bits forming modulation redundancy bits;
• the scrambled user information, the modulation redundancy bits, and the RS redundancy bits being provided to an arbitrated sector buffer such that the scrambled user information, the modulation redundancy bits, and the RS redundancy bits being segregated from each other within the arbitrated sector buffer;
• and
• the scrambled user information, the modulation redundancy bits, and the RS redundancy bits being provided from the arbitrated sector buffer and written to storage media of the HDD.

A method, comprising:

• receiving a plurality of user information;
• encoding first user information of the plurality of user information thereby generating first scrambled user information and first modulation redundancy bits;
• encoding second user information of the plurality of user information thereby generating second scrambled user information and second modulation redundancy bits;
• outputting a modulation encoded codeword that includes the first scrambled user information, followed by the second scrambled user information, followed by the first modulation redundancy bits, followed by the second modulation redundancy bits;
• performing RS (Reed-Solomon) encoding of the modulation encoded codeword thereby generating a RS codeword that includes RS redundancy bits, wherein the first scrambled user information and the second scrambled user information form scrambled user information, and the first modulation redundancy bits and the second modulation redundancy bits form modulation redundancy bits;
• and
• outputting the scrambled user information, the modulation redundancy bits, and the RS redundancy bits such that the scrambled user information, the modulation redundancy bits, and the RS redundancy bits are segregated from each other.