RMA communication involved specially designated regions of memory called windows. Recall that RMA actions utilize the following fundamental process:

1. Globally initialize a window for communication
2. Start an RMA epoch (synchronization)
3. Perform communication calls as desired
4. Stop an RMA epoch (synchronization)
5. Free window and any other resources

The first step is to create the window, and the last step is to destroy it. The next few pages explain how to use the MPI calls that create and destroy RMA windows.