Ernest Chang

Ernest Chang is named as one of the two authors of the Chang and Roberts algorithm, a ring-based coordinator election algorithm for distributed computing that he published with Rosemary Roberts in 1979. The algorithm assumes every process has a unique identification number and that the processes are arranged in a unidirectional ring in which each sends to its clockwise neighbour. A process that notices there is no leader sends an election message carrying its own identifier around the ring, larger identifiers are forwarded, smaller ones are replaced or discarded, and the process that receives its own identifier back becomes leader and announces itself with an elected message. The method works for any number of processes without any of them knowing how many there are. This entry records him as co-originator of that algorithm; no biographical page was found that would support more about his career or affiliation, so none is claimed.