Buffer system using parity checking of address counter bit for detection of read/write failures

摘要

A data buffer has a storage array that is addressable for read and write operations by an address of n bits that are supplied by a read address counter and a write address counter that each have n+1 bits. The n+1th bit is in effect a counter for passes through the array by the read and write circuits. During a write operation the n+1th bit of the write counter is stored as part of a parity bit for the addressed array location. During a read operation the n+1th bit of the read address counter is entered into a parity checking function on the word read from the addressed location. An errror is signaled if the n+1th bit of the read address counter does not agree with the n+1th bit of the write counter at the time of the write operation. For example, an error is detected if the write circuits fail and the read circuits make a second pass through words that have previously been read. The same entries on a next pass through the array.