Fault-Tolerant Systems

CHAPTER 3 Information Redundancy

Errors in data may occur when the data are being transferred from one unit to another, from one system to another, or even while the data are stored in a memory unit. To tolerate such errors, we introduce redundancy into the data: this is called information redundancy. The most common form of information redundancy is coding, which adds check bits to the data, allowing us to verify the correctness of the data before using it and, in some cases, even allowing the correction of the erroneous data bits. Several commonly used error-detecting and error-correcting codes are discussed in Section 3.1.

Introducing information redundancy through coding is not limited to the level of individual data words but can be extended ...