Parallel Merge Sort on Concurrent-Read Owner-Write PRAM

. This paper discusses a variant of the CREW PRAM model introduced by Dymond and Ruzzo called CROW (Concurrent Read Owner Write) PRAM. in which each global memory location may only be written by its assigned owner processor. We show that CROW PRAMs can sort in O(log n) parallel time using O(n log n) processors. 1 Introduction The PRAM (Parallel Random Access Machine) model for parallel computation was introduced as "a collection of synchronous processors executing in parallel and communicating via a global shared memory" by Fortune and Wyllie [FW78]. Their model satisfies the CREW (Concurrent-Read, Exclusive Write) convention for accesses to global memory. Dymond and Ruzzo proposed a natural and frequently occurring restriction of the CREW PRAM, called CROW (Concurrent Read Owner-Write) PRAM machines, for which each global memory location is assigned a unique owner processor and the owner is the only processor allowed to write into that cell throughout the course of a computation [D..