Checksum
A small fingerprint of data used to detect corruption or verify integrity.
Filesystems like ZFS checksum every block so they can detect and, with redundancy, automatically repair silent corruption (bit rot).
Related articles
ZFS
An advanced filesystem and volume manager offering data integrity, snapshots, compression and software RAID.
Bit Rot
The slow, silent corruption of stored data over time due to hardware imperfections.
ECC RAM(Error-Correcting Code Memory)
Memory that detects and corrects common data errors on the fly for greater reliability.