- Parity
- Parity is a term referring to the number of odd, or even 1 bits in a byte or word. Parity is used as an error-checking method to detect single-bit errors in the data.
- Parity Checking
- Parity Checking is the process of using parity values to verify the integrity of computer data.
Parity is used at the physical layer to check the integrity of data stored in computer memory (RAM), in serial data transmission, between mainframes and computer terminals, and between dial-up modems. Parity checks are necessary because computer memory can fail and interference and noise can disrupt the transmission of digital data causing the value of ones and zeroes to change to the opposite value.
The parity value is calculated before data is sent, and recalculated when received. If there is a difference in the actual parity of the data from the value of the parity bit, the data is corrupt. Parity checking does not allow for correcting the error, only for detecting errors.