5 Types of Real-Time Operating Systems

In today’s world of embedded systems, Real-time Operating System (RTOS) has become an important component. This operating system specifically manages and controls time-critical tasks in real-time. So, in today’s blog post, we will take a closer look at Types of Real-time Operating Systems (RTOS), their structure, Characteristics of real-time operating system and benefits of RTOS.

What is a Real-Time Operating System (RTOS)?

The full form of RTOS is Real Time Operating System. Real time operating system (RTOS) is an operating system specifically designed to run time-sensitive application programs. This RTOS works like other operating systems like Windows, Linux and macOS. The real-time operating system is designed in such a way that it can complete any task within a time limit. So, it works very fast.

RTOS manages tasks and resources. Apart from this, it also ensures that the work is completed within the time limit. It schedules the tasks in priority basis and the scheduler executes all those high-priority tasks. The scheduler is responsible for allocating processor time to tasks.

Architecture of RTOS

The architecture of an RTOS is generally divided into three main components: the kernel, device drivers, and application software.

  • The kernel is the heart of the RTOS. So, It is responsible for managing system resources, scheduling tasks, and providing real-time services. The kernel also provides a set of APIs that application software can use to access system resources.
  • Device drivers are software modules that interface with hardware devices such as sensors, motors or communication devices. It is also responsible for controlling the device and communicating with the kernel.
  • Application software is the topmost layer of the RTOS. By using this the users can easily do all kinds of work in the system. This application software communicates using system calls provided by the kernel.

Types of Real-Time Operating Systems

RTOS is basically designed to handle real-time applications and execute them in real-time. There are several types of real-time operating systems, each has its own characteristics of real-time operating systems and areas of application. Let us look at some common types of RTOS.


Hard real-time operating systems are designed to meet strict timing constraints and guarantee that critical tasks are executed within specific time limits. These systems prioritize time-critical tasks and ensure that they are completed without delay. Failure to complete within the time limit in a hard real-time system can have critical consequences. For example Car airbag deployment at the time of a crash.


Soft real-time operating systems also deal with time-sensitive tasks, but they are more flexible in meeting deadlines. These operating systems prioritize real-time tasks but also accept slight delays in completing that task. Soft real-time systems sometimes miss deadlines but this does not create much critical consequences. examples of soft real-time operating systems are to withdraw money from ATMs.


Firm real-time operating systems fall between hard and soft real-time systems in terms of their response requirements. They prioritize real-time tasks but allow the occasional missed deadline, as long as the system can recover and complete the task within a reasonable time frame. Firm real-time systems are often found in multimedia applications.

Embedded RTOS

These operating systems are basically designed for embedded systems. Embedded real-time systems are used in a variety of applications, including electronics devices, automotive systems, and Internet of Things devices, etc.

Distributed RTOS

These types of operating systems are designed to manage real-time applications spread across multiple interconnected devices or nodes. Distributed real-time systems are commonly used in areas such as distributed control systems, smart grids, and distributed sensor networks.

Characteristics of real-time operating system

There are several characteristics of real-time operating systems that smoothly process tasks. Let’s know about the features.

  • RTOS determines the execution of a task. It determines the specific time at which the task is to be executed. In this response times is highly predictable.
  • This operating system executes according to the priority of the task. It executes higher-priority tasks first, then lower-priority tasks. This feature ensures that the most important tasks are executed first, and the system responds quickly to real-time events.
  • RTOS provides fast interrupt handling, which means it can handle interrupts that may occur in the system. such as responding to input or communication signals. It can interrupt the current task running in the system and execute the Interrupt Service Routine (ISR) to handle the event.
  • RTOS is occupy very less memory & minimal resources for processing power. This feature is essential for embedded systems with limited resources.

Benefits of RTOS

  • RTOS provides increased reliability by ensuring that tasks can be executed within a specified time frame. This feature plays an important role in security systems such as medical devices, aviation and automotive systems.
  • Real-time operating systems make it easier to develop and execute applications. This is because any kind of complex work is divided and executed, which is easy.
  • This operating system always provides better system performance, so that tasks can be executed efficiently and faster. It assigns priority to the task of the system and executes that task in a sequence manner as per priority basis.
  • Real time operating system requires very little memory or less space in the system to operate.
  • A real-time system is a set of pre-built libraries and tools that are used to rapidly develop real-time applications. This feature speeds up system development and reduces cost.

Related Article


Real-time operating systems (RTOS) have become an essential component of embedded systems. Here is the ability to execute a task within a specific time frame.

I hope that in today’s article, you must have understood about 5 types of real-time operating systems, the characteristics of real-time operating systems and the benefits of RTOS. If you have any kind of doubt regarding this article, then you can tell us. We will try our best to solve your problem.

If you like this article, then share it as much as possible so that this type of information reaches all the students.

!!Thanks for reading this article!!

Leave a Comment