Abbreviation for Error-Correcting Code.
ECC is an algorithm which is used to detect and correct (if possible) errors in data communication and storage.
It's a kind of redundant data handling, where the ECC code (ECC byte) is calculated from the valuable data which is protected by this code.
With proper implementation the system can detect if the collected data is corrupted or not. It's based on the re-calculation of the ECC code. If the new value equals to the code attached to the data, the system should consider that the data is intact. If not, the data is corrupted.
Error correction is possible only if the Hamming-distance of valid ECC values is greater than 1. The count of correctible errors in a system is: FLOOR( d / 2, 0 ), where d is the count of valid ECC values.
In most cases ECC is used to detect errors only.