Message Passing Model
- Communicate through explicit I/O operations
- Essentially NUMA but integrated at I/O devices vs. memory system
- Send specifies local buffer + receiving process on remote computer
- Receive specifies sending process on remote computer + local buffer to place data
- Synch: when send completes, when buffer free, when request accepted, receive wait for send
- Send+receive => memory-memory copy, where each supplies local address, AND does pair-wise synchronization!