Method for Changing Selected Bits or Bit Fields within Parity Protected Data without Recalculating Parity while Maintaining Parity Protection
Original Publication Date: 2003-Oct-22
Included in the Prior Art Database: 2003-Oct-22
A method for changing selected bits or bit fields within parity protected data is described that allows the data to be modified without having to calculate the parity bit while still maintaining parity protection. The method uses the fact that parity protection only detects an odd number of bit errors leaving even number of bit errors going undetected. Therefore, for any bit which needs to be changed independently of the other bits, the method provides two bits of representation in the parity protected data word. This creates an even number of bits changing state, which preserves the state of the parity bit. This method can be used anywhere parity is used providing a wide range of applications including data storage and data transmission devices. Examples of data storage devices include magnetic media, disc drives, memory systems, and cache arrays. Data transmission includes both parallel and serial transmission either wired or wireless.