Parity checking is a technique used to detect errors in digital data storage on a computer. This method adds an additional parity cell to each 8-bit byte of memory, making it a nine-bit structure to ensure accuracy.
Even Parity and Odd Parity: What’s the Difference?
In even parity systems, a 1 parity bit is added to a byte if there is an odd number of bits, resulting in an even number of bits. On the other hand, odd parity systems add a 0 parity bit to a byte if there is an even number of bits, resulting in an odd number of bits.
Limitations of Parity Checking
While parity checking is useful for detecting single-bit errors, it cannot identify two-bit errors. When a byte is sent, the parity bit is examined for any mistakes. If a single bit has been mistakenly swapped from 1 to 0 or vice versa, the parity system can detect this. However, if two bits are inverted, the even or odd number remains the same, making it impossible to identify a two-bit error. For a more reliable system, error-correcting codes (ECC) are recommended.
Frequently Asked Questions
What is a parity bit?
A parity bit is an extra digit added to a binary code with either odd or even parity that checks for errors in transmission when stored data is read.
How does even parity work?
In an even parity system, an additional parity bit is added to a byte to ensure that the total number of bits is always even. If there is an odd number of bits, the system adds a 1 parity bit to the byte.
How is parity checking different from ECC?
Parity checking is a basic method used for identifying single-bit errors, whereas ECC is a more reliable and efficient system that not only detects but also corrects multiple errors in data storage.
The Bottom Line
Parity checking is a basic error-detection technique that checks the accuracy of digital data stored on a computer. With its limitations in detecting only single-bit errors, it is recommended to use more reliable systems such as ECC for efficient error correction and detection.