A cyclic executive is an alternative to a real-time operating system. It is a form of cooperative multitasking, in which there is only one task. The sole task is typically realized as an infinite loop in main(), e.g. in C. int main(void){ // initialization code here while (1) { currTemp = tempRead(); lcdWrite(currTemp); // waste CPU cycles until 50 ms lcdWrite(currTemp); // do other stuff // waste CPU cycles until 100 ms }} The outer 100 ms cycle is called the major cycle. In this case, there is also an inner minor cycle of 50 ms.