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Table of contents
Real-Time Operating System
Components of RTOS
Types of RTOS 
Hard Real-Time operating system
Soft Real-Time operating system
Firm Real-time
Advantages of Real-time operating system
Disadvantages of the Real-time operating system
Frequently Asked Questions
What is the importance of RTOS?
Write the main features of  RTOS.
What is the difference between real-time OS and normal OS?
Write the difference between time-sharing and real-time operating systems.
Give some examples of Real-time operating systems.
Last Updated: Mar 27, 2024

Real-Time Operating System

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Anubhav Sinha
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25 Jun, 2024 @ 01:30 PM
Operating System


Operating system software handles computer operations such as editing, input/output operation, resource allocation, file system manipulation, etc., and acts as a visual interface between user and hardware. There are different types of operating systems which are-

In this article, we are going to discuss about the Real Time Operating System in detail.

So, let’s get started: 

Also see: Multiprogramming vs Multitasking and Open Source Operating System

Real-Time Operating System

A real-time operating system (RTOS) is a specially designed operating system used in computers with strict time limits for any work to be done. It is widely used in those systems where calculation results influence the process while executing.

In RTOS, the processing time required is calculated by ten incremental seconds. It is a time-limited system defined as fixed time constraints. In this type of system, processing should be done within the specified parameters. Otherwise, this will lead to system failure. 

Examples of real-time operating systemsFlight traffic control systems, Command Control Systems, Heart pacemakers, Airlines Booking systems, Multimedia Network Systems, Medical Imaging Systems, Cell phone switching gadgets, Robots, etc.

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Next, let us discuss the components of an RTOS:

Also Read About, FCFS Scheduling Algorithm and Difference Between Bit and Byte

Components of RTOS

RTOS is system software that controls computer hardware and software resources and provides essential services to computer programs. It acts as a link between the computer user and the computer hardware like any other operating system. We can perform computer programs efficiently and easily using the operating system. There are several different tasks performed within the system, and it responds appropriately to every task in short intervals. This makes real-time systems compatible with systems. 

There are various components of Real-time operating systems which are given below-

Components of RTOS

The Scheduler: This component of RTOS tells the order of the tasks in which it can be executed which are usually based on priorities.

Function Library: It is an important RTOS feature that serves as a visual connector that helps you to connect the kernel and application code. This application allows you to send requests to Kernel using the library so that the app can provide the results you want.

Fast dispatch latency: It is an interval between the termination of the task that can be identified by the OS and the actual time taken by the thread, which is in the ready queue, that has started processing.

User-defined data objects and classes: The RTOS system uses programming languages ​​such as C or C ++, which must be configured according to their functionality or operation.

Memory Management: this feature is required in the system to allocate memory to every program, which is a very important part of RTOS.

Symmetric Multiprocessing (SMP): It is a number of different functions that can be managed by RTOS so that parallel processing can be done.

Must Read Multiprocessing Operating System

Types of RTOS 

Now it’s time to discuss the types of RTOS which are generally of three types as discussed below-

Types of RTOS

Hard Real-Time operating system

In Hard RTOS, all important tasks must be completed within the allotted time, that is, within the given deadline. Failure to meet the deadline could result in serious failures such as mechanical damage or even loss of human life.


For Example- Autopilot travel simulators, Medical critical care systems, Aircraft systems, etc.

Soft Real-Time operating system

Soft RTOS accepts a few delays while using the Operating System. In this type of RTOS, there may be a closing date assigned to a specific task, but a short delay is acceptable. Therefore, cut-off dates are treated softly via means of this kind of RTOS.


For Example- Online Transaction systems and Livestock price quotation Systems.

Firm Real-time

These types of RTOS also need to follow a deadline. However, bypassing the deadline may not have the greatest impact but may result in unwanted impacts, such as a significant reduction in product quality.


For Example- Different types of Multimedia applications.

Must Read Process Management in OS

Advantages of Real-time operating system

The benefits of the real-time operating system are as follows-:

  • It is easy to plan, develop and use real-time applications under a real-time operating system.
  • Real-time performance structures are highly compact, so those structures require very little memory space.
  • In a Real-time operating system, there is high usage of devices and systems.
  • Memory sharing is best controlled on these types of systems.

Disadvantages of the Real-time operating system

Following are the cons of a Real-time operating system-

  • Real-time operating systems have complex architecture and are very expensive to upgrade.
  • Real-time applications are extremely complex and can consume significant CPU cycles.

You can also read about layered structure of operating system.

Must Read Threads in Operating System

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Frequently Asked Questions

What is the importance of RTOS?

  • It provides pre-programmed editing, which allows you to separate analytical processing and non-critical processing.
  • Real-time OS provides API functions that allow for clean and minimal application code.
  • Short-term dependence and work-based design create interdependence between modules.

Write the main features of  RTOS.

  • Take very little memory
  • Use very few resources
  • Response times are highly predictable
  • Unexpected location.
  • Kernel saves the ad status of the interrupted activity and decides which task to launch next.
  • Kernel restores function status and shifts CPU control to that task.

What is the difference between real-time OS and normal OS?

The difference between standard and real-time applications is a time factor. Time is not an important factor in normal operating systems like Windows, Linux, Unix, etc. Time is a very important factor in real-time applications used in the launch of rockets, ATMs, etc. 

Write the difference between time-sharing and real-time operating systems.

Many users can interact with computer systems simultaneously using time-sharing operating systems, which switch the CPU between them. On the other hand, a real-time operating system may be able to complete one task at a time and deliver resources on time.

Give some examples of Real-time operating systems.

Some examples of Real-time systems are-

  • MTS
  • Lynx
  • QNX
  • VxWorks etc.


To summarize this blog, we learned about real-time operating systems, different types of operating systems, and components. Further, we also discussed the three types of real-time operating systems which are soft, firm, and hard RTOS. And then we learned about the advantages and disadvantages of Operating System.

Recommended Readings: 

Do check out The Interview guide for Product Based Companies as well as some of the Popular Interview Problems from Top companies like Amazon, Adobe, Google, Uber, Microsoft, etc. on Coding Ninjas Studio. You can also consider our Operating System Course to give your career an edge over others.

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Happy Learning!

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