Cyclic Redundancy Check

aliases:

A form of error-correcting code that's used to detect accidental changes or corruption in digital data. It's used in GPT volumes.

Any block of data that's entering the storage system get's a short check value assigned to it, based on the remainder of a polynomial division of their contents (all being numbers). Every time the data is retrieved, the calculation of the check value is repeated and if there's a difference between the current and the past value, something has gone wrong.