Coding method and decoding method, coder and decoder, and chip, hard disk, and communication system

A coder, comprising:

• a receiver, a processor and an error correcting coder, wherein
• the receiver is configured to obtain target data;
• the processor is configured to determine, from a plurality of error correcting codes based on a data length of the target data, at least one error correcting code corresponding to the target data, the target data is data obtained by performing data alignment on raw data and then performing data compression, and at least some of the error correcting codes have different lengths;
• and
• the error correcting coder is configured to perform error correcting encoding on the target data based on the at least one error correcting code corresponding to the target data, to obtain at least one error correcting codeword.

An error correcting decoding method, comprising:

• obtaining at least one error correcting codeword;
• determining, from a plurality of error correcting codes based on a length of the error correcting codeword, an error correcting code corresponding to the error correcting codeword, wherein at least some of the error correcting codes have different lengths;
• and
• decoding the error correcting codeword based on the error correcting code, to obtain decoded data.