Paritásellenrzés

Paritásellenrzés, or parity checking, is a simple error detection method used in digital communications and data storage. Its primary purpose is to detect single-bit errors that may occur during transmission or storage. The core principle involves adding an extra bit, known as the parity bit, to a block of data. This parity bit is calculated based on the number of '1' bits in the original data.

There are two main types of parity: even parity and odd parity. In even parity, the parity bit is set to '0' or '1' such that the total number of '1' bits in the data, including the parity bit, is even. Conversely, with odd parity, the parity bit is chosen to make the total count of '1' bits odd.

When data is received, the parity check is performed again on the received data, including its parity bit. If the calculated parity matches the received parity bit, it is assumed that no error has occurred. However, if there is a mismatch, it indicates that an error has likely taken place.

While effective for detecting single-bit errors, parity checking has limitations. It cannot detect an even number of bit errors, such as two bits flipping, as the parity will still appear correct. Furthermore, it does not provide any mechanism for correcting the detected errors. Despite these limitations, parity checking remains a fundamental and widely used technique due to its simplicity and low computational overhead, often serving as a first layer of defense against data corruption.