RTOS – the heart of industrial automation systems

In the era of digitalization and industrial automation, embedded systems play a crucial role in controlling machines, robots, and IoT devices. To provide reliable operation within strictly defined time constraints, a real-time operating system (RTOS) is essential. RTOS ensures smooth operation in systems where real-time response, predictability, and precise scheduling are required. In this article, we will explain what a real-time operating system is, the approaches to task management in embedded systems, the different types of RTOS, the benefits they provide, and their applications.

Real-Time Operating System (RTOS) – what is it and why was it created?

Before discussing how real-time operating systems work and why they were developed, it is essential to first recall how traditional operating systems (OS) function. This perspective helps to understand the purpose of RTOS and how they differ from conventional OS.

An operating system is software that runs on a computer or microcontroller. Its task is to manage background processes and handle user applications. The system kernel manages running processes in such a way that each one is allocated CPU time and other resources, ensuring its uninterrupted operation. To visualize this, we can imagine, for example, a computer running a web browser, some programs, and a mouse and keyboard interface simultaneously. The user can switch seamlessly between them as the operating system manages their execution in the background, allocating resources such as CPU power, RAM, and disk access.

The main purpose of operating systems is to ensure adequate interaction between software and humans. Therefore, task execution order is arranged in a way that delays are acceptable to the user. In traditional operating systems, task scheduling is non-deterministic, meaning that response times are not guaranteed in general-purpose operating systems. In short, it is not known when exactly a task will be executed or how long it will take.

RTOS – deterministic and fast operation system

In many applications, we need a system that enables precise management of real-time tasks. This is where an RTOS comes into play, providing mechanisms that meet strict time constraints and deadlines. RTOS systems are used in situations requiring rapid responses to events, such as in the automotive industry, where airbags must deploy instantly or when the engine warning light must illuminate at the right moment. The response to these events must occur within a defined time frame, by gaining priority, and interrupting other running tasks. Since its absence can lead to serious consequences, the RTOS provides real-time control, ensuring efficient handling of critical tasks.

Approaches to task management in embedded applications – Super Loop vs. RTOS

Super Loop (SL) is one of the simplest approaches to microcontroller programming, commonly used in small embedded applications. SL is a program where tasks are executed sequentially, meaning task 1 is completed first, followed by task 2, then task 3, and so on. The advantage of the Super Loop is its simple implementation and low resource consumption, as it does not require a large amount of memory to manage multiple threads. However, its limitation is the lack of a defined task execution time, which can lead to situations where a single task takes too long. This can result in the loss of important data, processing outdated information, or slowing down the entire system.

RTOS – advanced, real-time task management

RTOS is a more advanced approach that manages multiple tasks simultaneously and allocates system resources based on their assigned priorities. Unlike the Super Loop method, RTOS allows multiple tasks to run concurrently using a Scheduler. Each task operates in a separate thread, and the RTOS determines when, how often, and for how long each task should be executed based on priorities. Cooperative and priority-based scheduling helps ensure that critical tasks are not delayed. Deterministic execution guarantees that tasks will be completed within a specified time, and priority management enables the interruption of less critical tasks to handle essential processes. The limitation of the RTOS approach is its higher resource consumption such as RAM and Flash memory, greater code complexity, and more challenging debugging compared to the Super Loop method. Additionally, the Scheduler must be tailored to the application’s requirements to ensure it operates as expected.

Types of Real-Time Operating Systems. How can they be categorized?

From simple to advanced RTOS

There are RTOS systems that include only a task scheduling module. In such cases, the developer must implement or import a file system and device drivers themselves to customize the RTOS to their requirements. Examples of high-level device drivers include Wi-Fi, Bluetooth, or LCD drivers for microcontrollers. RTOS can work with them, but they typically require separate implementation. Depending on the application, one can choose lightweight RTOS solutions like FreeRTOS or more complex options such as Zephyr, VxWorks, or QNX.

Based on response time

Depending on the strictness of time constraints, real-time operating systems can be classified as soft, firm, or hard RTOS. Each of these types differs in how they handle delays and the consequences of their occurrence.

Soft real-time operating systems

Soft real-time operating systems prioritize minimizing delays, but occasional delays do not result in catastrophic failures. Such systems strive to deliver results within a specified time but allow for slight time overruns. These delays may affect system performance quality but do not lead to its failure. Soft real-time systems are used in applications such as audio and video processing, where short delays may degrade transmission quality but do not completely stop it. For example, when adjusting the volume of music in a car, it does not matter significantly whether the response happens 100 milliseconds earlier or later — the most important thing is that the task was completed.

Firm real-time operating systems

These systems are more stringent than soft RTOS but still allow for occasional time overruns without big consequences. Executing a task within a specified timeframe is required, and minor delays may impact performance but do not render the entire system inoperative. A real-world example of such a system is the delay in turning on a car’s turn signal. If the maneuver has already been executed, it does not matter if the signal activates later.

Hard real-time operating systems

These systems operate under strict constraints where any delay can lead to severe consequences, such as system failure, life-threatening situations, or significant financial losses. In such systems, all operations must be executed within precisely defined time limits, and any deviation is unacceptable. Hard RTOS ensures that real-time capabilities are met in these demanding environments. Examples include air traffic control systems, braking systems, airbag deployment in automotive applications, or medical devices, for example patient monitoring systems, in which every millisecond matters, and even the smallest delays could pose serious health or life risks.

Benefits of Real-Time Operating Systems – at a glance

• Deterministic operation – RTOS ensures predictable response times, crucial for systems requiring precise timing.
• Efficient task management – The scheduling mechanism prioritizes tasks and ensures their timely execution.
• Multitasking support – It allows the simultaneous execution of multiple tasks without blocking critical operations.
• Optimal resource utilization – RTOS efficiently manages memory and processor time, essential for embedded systems with limited resources.
• High reliability and stability – It is designed for demanding environments such as industrial automation, healthcare, and aviation.
• Fast response to sudden events – Interrupt handling and queueing mechanisms provide instant reaction to critical situations.
• Integration with microcontrollers and IoT devices – It is optimized for low-power operation, making it ideal for embedded and IoT applications.

Discover Albatros – RTOS designed for reliability and precision!

Albatros is a real-time operating system developed by AIUT engineers, ensuring deterministic operation, high performance, and optimal resource management. It is used in real-time embedded applications, such as advanced media monitoring systems, urban infrastructure management, industrial automation, real-time location systems, and autonomous mobile robots, guaranteeing stability and operational security in demanding conditions.

Find out how Albatros RTOS can enhance the efficiency of your systems!

Summary

RTOS plays a key role in real-time embedded applications — from robotics and industrial control to IoT devices and autonomous vehicles. Thanks to its predictability, deterministic operation, and efficient resource management, it is used in the most demanding environments. Its reliability and precision make it an essential component of systems where every millisecond counts. RTOS processes data, providing real-time performance for industrial automation, medical applications, or automotive systems.