Links Error Checking Most memory available today is highly reliable.
Most systems simply have the memory controller check for errors at start-up and rely on that.
Parity chips have an extra bit for every 8 bits of data. The way parity works is simple. Let's look at even parity first. When the data is read back out of the bits, the total is added up again and compared to the parity bit. The problem with parity is that it discovers errors but does nothing to correct them.