History of The Actor Model - Models Prior To The Actor Model - Threads, Locks, and Buffers (channels)

Threads, Locks, and Buffers (channels)

Prior to the Actor model, concurrency was defined in low-level machine terms of threads, locks and buffers(channels). It certainly is the case that implementations of the Actor model typically make use of these hardware capabilities. However, there is no reason that the model could not be implemented directly in hardware without exposing any hardware threads and locks. Also, there is no necessary relationship between the number of Actors, threads, and locks that might be involved in a computation. Implementations of the Actor model are free to make use of threads and locks in any way that is compatible with the laws for Actors.