The first communication mechanisms use the OSEK Messages support capabilities provided by MicroC.
The first of those, Non-Queued messages, uses a message identifier (i.e. the message name) to share data between various tasks in the application. The sender and or receiver TASK of such a message might be running in the same ECU, sharing the same memory address space, or running across an ECU network on some remote MCU. The user of the message need not be aware of the concrete implementation. Thus, using that mechanism ensures that the resulting design is correct, flexible and efficient.