NLP programming automates the translation process between computers and humans by manipulating unstructured data words in the context of a specific task conversation.
View Full Term. By clicking sign up, you agree to receive emails from Techopedia and agree to our Terms of Use and Privacy Policy. A parity error is an error that results from irregular changes to data, as it is recorded when it is entered in memory. Different types of parity errors can require the retransmission of data or cause serious system errors, such as system crashes. The source of a parity error is a parity bit or check bit.
This bit is added to a byte or other piece of code to show whether the number of bits included is even or odd. If this parity bit is checked later and found to be inaccurate, it can trigger a parity error.
Experts have separated parity errors into two categories — soft parity errors and hard parity errors. Soft parity errors are often caused by electromagnetic field conditions, such as background radiation, electromagnetic interference or static discharge events. Hard errors may be caused by power surges, overheating, manufacturing defects or other causes. If the result of all the enabled data bits is odd, the parity bit is set to 0 disabled so that the odd number of enabled bits is retained.
After the parity bit has been set, the byte of data and the parity bit are written to memory. Note that even parity works the same way, only it looks for an even number of enabled bits; if the number of enabled bits is odd, then the parity bit is enabled.
When the CPU requests data from memory, the data byte is retrieved along with the parity bit that was generated when the byte of information was stored in memory.
The system looks at the data byte and calculates whether the parity bit stored in memory should be set to 1 or 0. It then compares the answer it has just generated with the value of the parity bit stored in memory. If the two match, the integrity of the information in memory is considered okay, the parity bit is stripped from the data byte, and the data is delivered to the CPU.
If the two differ, you have a parity error, meaning that there is a problem with the integrity of the data stored in memory. Parity checking adds an extra parity cell to each 8-bit byte of memory, thus creating a nine-bit structure. In an "even parity" system, a 0 is stored in the parity bit if there is an even number of bits in the byte; if an odd number, a 1 is stored to make the total number of bits even.
In "odd parity" systems, the opposite occurs; a 0 parity bit if odd, a 1 parity bit if even to make the total number odd. One-bit parity systems will detect if one of the eight bits in the byte has been erroneously switched from 1 to 0 or from 0 to 1.
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