What does "coding" mean in this context?
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Take a message we want to communicate and add some additional data that allows recovering the message even if part of it is corrupted. The hard part is choosing what additional data to include to recover from enough corruption with small overhead and in a reasonable runtime.
These are used everywhere from WiFi to hard drives to QR codes to RAM chips -- the ECC in ECC RAM being "error correcting code" and now partially mandatory with DDR5.