A manner of checking the integrity of a set of data by summing all of the bytes of data, or otherwise combining through a series of arithmetic or other logical operations.The originating device appends the result of the calculation to the data set prior to storing or transmitting the data. The device that retrieves the stored data or receives the transmitted data repeats the calculation and compares the two checksums. If the two do not match exactly, it is assumed that the dataset is errored.This process detects many, but not all, errors, and includes no mechanism for error correction. Checksum is employed in an error control mode known as recognition and retransmission. See also cyclic checksum, error control, LRC, and recognition and retransmission.