What Does Parity Mean?

Parity refers to the redundant check bit that represents the even/odd condition of a certain unit (usually one byte) of computer data stored in the RAM of a device. This is used to check and double check for errors by comparing the stored and the computed parity. Parity bits are stored in additional individual memory chips, with 9 bits for every 8 bits of actual data.


Parity is also known as random access memory (RAM) parity.

Techopedia Explains Parity

During the early years of computers, it was common for users to experience faulty memory and parity issues. A parity bit was hence required to check and detect errors in memory. A parity error causes the system to stop, which causes the loss of any unsaved data. This is generally a better choice than saving corrupt data. To save space, sometimes logic parity RAM is used, which uses an 8-bit RAM in the same style as a 9-bit parity RAM. This is the reason why logic parity RAM is also sometimes known as “fake parity RAM.” Modern computers do not support parity error detection anymore owing to the risk of data loss and corruption.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.