Online Training Session: Messages for Intertask Communication
|Messages for Intertask
• “Indirect” Message Passing
• “Direct” Message Passing
• Asynchronous Data Communication
• Tasks and their Message Queues
• Sending a Message
• Receiving a Message
• Do All Communication with Messages!
This online training lesson contains material taken from our past classroom-based introductory courses. This
particular section presents the basic approaches to message passing for communication between concurrent tasks.
In an actual training course, this section would be preceded by introductory sessions covering the fundamental
definitions of embedded and real-time systems, as well as the fundamentals of multi-tasking (priority-based
pre-emptive task scheduling). This section would be followed by a presentation of the detailed syntax of real-time
operating system ("RTOS") service calls for message sending and receiving, then examples of how to write programs
that do this in a multi-tasking environment, and then student exercises.
This page lists the issues that will be discussed in this lesson. "Direct" and "Indirect" message passing will be
compared and contrasted, as will be "Synchronous" and "Asynchronous" message passing. Message queueing
issues will be covered. This will be followed by step-by-step "cookbooks" to guide the programmer in setting up
message communications in his/her software.
Message passing is the most popular technique for transferring data between software tasks in a multi-tasking
software environment. This lesson will end with a page discussing how message passing can be used even in
situations where semaphores have traditionally been used.
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This page Updated March 25, 2016