PPT Slide
Memory Protection - an MMU feature which allows address ranges on page boundaries (a minimum size memory block) to be specified as read-only - if an update to such a range is attempted, the MMU will assert an NMI exception.
Message Queue - an RTOS software mechanism which abstracts shared memory data into atomic enqueue and dequeue operations on a buffer controlled by the RTOS and known only to applications by an ID, accessable to them only through RTOS message queue operations. Operations are atomic with respect to threads only (not interrupts), and so most often only a message queue send is allowed in interrupt context - never a message queue receive.
Message Sequence Chart - a diagramming method used in the Specification and Design Language (SDL) as well as UML (Universal Modeling Language) which shows threads of execution and all messages (or function call interfaces) which associate the threads in a protocol.