Real Time Operating System (RTOS) and Its Types

In this tutorial, we will learn about the real time operating system (RTOS) and its different types. By Monika Sharma Last updated : May 05, 2023

Real Time Operating System (RTOS)

The Real-Time Operating System works with the time constraints which are subjected to the real world. What this simply means is that the job assigned to the Operating system must be completed within the assigned deadline.

Note: Here, deadline means the time before which the assigned job or task must be completed by the Operating System.

In the day to day life, we come across many such gadgets and appliances which work on RTOS. For example, our alarm clocks, washing machines, microwave ovens, etc.

Types of Real Time Operating Systems

There are two types of Real-Time Operating System: 1) Hard Real-Time OS and 2) Soft Real-Time OS. This classification of the Real-Time Operating System is done on the basis of the strictness of the assigned deadline.

1. Hard Real Time Operating Systems (Hard RTOS)

In the Hard RTOS, the deadline is handled very strictly. What this means is that the assigned task must be executed on that particular scheduled time, and must be completed within the assigned time limit. In this type of RTOS, the system cannot afford any sort of delays. If there occurs a delay in execution of the task, then the Operating System simply aborts the task. However, the Hard RTOS systems are designed very precisely in such a way that every assigned task gets executed and completed on time and there occurs no case with any sort of delay. Such type of Operating Systems is used in cases where time plays a very vital role and every smallest fraction of time matters.

An example of such systems can be seen in Missile and Rocket Launch systems, Airlines controlling systems, Alarm Clocks.

2. Soft Real Time Operating Systems (Soft RTOS)

In the Soft RTOS, a few delays are acceptable by the Operating system. Here, there is a deadline assigned for a particular job, but a delay for a small amount of time is bearable. This means that the deadlines are handled softly by this type of RTOS.

Such a system was designed to deal with the cases where completing a job is more necessary than completing a task on accurate time, because aborting a process every time in case of delays will cause to restart the job again and again, and this is not an effective way to execute the tasks as it requires time and resources for any process to run.

For example, many household electronic gadgets used Soft RTOS like the washing machine, microwave ovens, etc.

What are the Services of an Operating System?

Dual Mode Operations in Operating System