Messages are written to and read from each circular buffer in a FIFO fashion as shown in this figure. “N” is the maximum number of messages that can be stored in a circular buffer and must be an even number. By default, N= 4 in the main IPC drivers. Every time the sending processor performs a “Put”, PutWriteIndex is incremented and every time the receiving processor performs a “Get”, GetReadIndex is incremented. There can be N-1 “Puts” into the circular buffer until the receiving processor’s application code must perform a “Get”.