Rate 16/17 (d=0,G=6/I=7) modulation code for a magnetic recording channel

Within a magnetic recording channel, a method for encoding a sequence of 16 bit digital data words into a sequence of 17 bit codewords in consonance with predetermined minimum zero run length (d), predetermined maximum zero run length (G) and maximum interleave zero run length (I) coding constraints for recording upon a magnetic medium, comprising the steps of:

• dividing the 16 bit data word into an 8-bit A byte:
• a1, a2, a3, a4, a5, a6, a7, a8;
• and an 8-bit B byte b1, b2, b3, b4, b5, b6, b7, b8,
• separately testing the A and B bytes for violation of coding constraints,
• generating P and Q code bytes from the A and B bytes and inserting a center bit C of value one or zero between the P and Q code bytes to form the 17 bit codeword, where C=0 indicates the presence of a coding violation in one or both of the A and B bytes, and where Enc.sub.1(A byte), Enc.sub.2(B byte) and Enc.sub.3(A,B bytes) are distinct functions each of which mapping into a coded byte that can be concatenated with C=0 and another validly coded byte to create the 17 bit codeword in accordance with the predetermined coding constraints.