Cyclic executive

A cyclic executive[1][2] is an alternative to a real-time operating system.

The sole task is typically realized as an infinite loop in main(), e.g. in C. The basic scheme is to cycle through a repeating sequence of activities, at a set frequency (AKA time-triggered cyclic executive).

For example, consider the example of an embedded system designed to monitor a temperature sensor and update an LCD display.

If the temperature sensor must be read every 100 ms for other reasons, we might construct a loop of the following appearance: The outer 100 ms cycle is called the major cycle.

We can use a counting mechanism to clarify the major and minor cycles.