54. What Is a Real-Time Operating System (RTOS)?
We like such topics! The Real-Time Operating System (RTOS) is a system that has two important features: predictability and determinism. In an RTOS, repetitive tasks are executed at a specified time. With a real-time operating system, we know how long a task will take and that it will always, but always, produce the same result.
In today’s lesson we will look at this interesting subject. What is an RTOS? Where do we use it? Read on and find out!
Real-Time Operating System (RTOS) – Definition
RTOS is nothing more than an operating system. However, it is very different from the systems we are familiar with, such as the OS in our phones that we use every day. RTOS is like a soldier – it is designed to quickly and efficiently perform the tasks assigned to it. It’s small, sometimes weighing just a few megabytes, has a simple graphical interface and has no unnecessary features, such as an internet browser.
Real-Time systems fall into two types:
- Soft ones that work within a few hundred milliseconds, on the scale of a human response.
- Hard ones that provide more answers and work within tens of milliseconds.
Real-time operating system (RTOS) features:
- Repeating the data in the input will always give us the same result.
- Very high performance. As we have already mentioned, this type of system is like a soldier – fast and responsive. It performs actions in a small fraction of a second.
- They are secure. Very often RTOS is used in critical systems where failures can have really catastrophic consequences (robotics, flight controllers).
- Priority-focused planning. What does this mean? That all high-priority activities are done first. Those that can wait, simply wait. The result? The RTOS will perform the most important task immediately.
- Small footprint. This type of operating system is a fraction of the size of the systems we use every day. For example: Windows 10 with updates takes up 20 GB.
How Does This Operating System Work?
As we mentioned earlier, RTOS systems are divided into soft and hard.
Soft RTOS systems tend to have larger file sizes, compared to hard systems. Soft RTOSes are usually used in systems where performing an action does not have to be done immediately. This type of system can be found in PCs, cameras or smartphones.
On the other hand, we have hard RTOS systems that have small to medium data files. They operate during critical moments of a given system’s workload. Typically used where systems need to perform important calculations, i.e. aircraft sensors, autopilot or medical devices.
It is worth knowing that in hard real-time operating systems, if a given calculation cannot be performed, then the entire operation fails. In a soft RTOS, the system still works, but individual tasks may be unproductive.
A Real-Time Operating System can also function as schedulers, where individual tasks can be planned, marked as ready for execution, or blocked.
Typically, these systems have a monolithic architecture composed of a kernel and microkernel. The kernel is the core of the entire operating system and is responsible for providing essential services to all other parts of the system. Kernels form the main layer between the operating system and the hardware.
The kernel of this system and all other operating processes share a single space. Therefore, this architecture runs fast, compared to other configurations. In practice, it provides better performance. However, they have a key disadvantage – it is more difficult to perform updates. Moreover, a programming error in the file data system, protocol or driver can cause the whole system to crash.
The microkernel and its entire architecture contains a single kernel and operations located in different locations. This architecture is slower than a monolithic RTOS. Why? Because each action must first return to the kernel before it can be transferred to the corresponding component being referenced. The microkernel also does not contain all the file systems.
Where Do We Use This Kind of Operating System?
Because of its many advantages, RTOS is most often used in embedded systems. Those that run behind the scenes of larger operations. Typically, RTOS does not have a graphical interface. Moreover, real-time operating systems are also used in intelligent edge devices (also known as electromechanical edge systems or cyber-physical systems).
RTOS also pays attention to complexity management. The code of a given project has different, independent threads. Thus, using a real-time system can streamline processes and help manage a given project more easily.
RTOS VS Cryptocurrencies
Maybe not exactly in cryptocurrencies, but this operating system has many challenges in the Internet of Things (IoT). As you know, this sector faces numerous challenges related to embedded systems. IoT developers have to solve problems of scalability, security or modularity. So how can RTOS be used in this sector?
Most of all – to scalability. If the Internet of Things provides users with more products, it will be even more attractive. Leveraging, and most importantly understanding, how an RTOS works can help some industries choose a real-time operating system that can scale and meet unique requirements for completely different use cases. An RTOS for IoT must meet the computing power, size and functionality needs of other IoT systems.
Connectivity. We can say that also presents a challenge for a real-time operating system in the case of IoT. RTOS must support popular and well-known protocols. On top of that, there are communication standards.
Security. RTOS implementation in the IoT sector will provide this feature.
Performance. RTOS must, and in fact does, offer a very robust feature set that will help IoT manufacturers differentiate their product offerings and give them a competitive edge.
An RTOS can be highly efficient for the Internet of Things. In the long term, this type of operating system can open entirely new possibilities for developing IoT solutions. Primarily, as mentioned before, RTOS enhances speed, security, and privacy.
What’s more, RTOS is an excellent basis for incorporating cutting-edge features into the IoT sector. The system’s operation and functionality offer IoT manufacturers a significant advantage.
Popular RTOS software products include:
- FreeRTOS by Amazon Web Services,
- QNX by BlackBerry,
- VxWorks by Wind River,
- SafeRTOS by Wittenstein.
A Real-Time Operating System is designed for real-time applications and processes that process data on the fly and cannot afford delays. RTOS gives us priority-focused scheduling that allows us to separate important actions from those that can wait.
An important feature of this system is that it takes up very little memory and uses fewer resources. Thus, it is very efficient, which is its key factor. Real-time operating systems are used in aviation or even medicine.
However, the biggest drawback of RTOS is that it only focuses on a few tasks at a time.