Correct single bit memory errors in hardware.
ECC memory maintains a memory system virtually
free from single-bit errors: the data read from each
word is always the same as the data that had been
written to it, even if a single bit actually stored, or
more in some cases, has been flipped to the wrong
state. Some non-ECC memory with parity support
allows errors to be detected, but not corrected;
otherwise errors that may occur are
not detected.