When developing a new IoT device or system, one of the earliest and most important decisions you’ll need to make is what kind of operating system it’s going to run off.

In this scenario, It’s normally a case of RTOS vs. OS. However, a lot of IoT developers go down an old-school route and opt for Bare Metal. 

The debate over which of the three is best for IoT is one that rumbles on amongst developers – with developers having staunch opinions on the matter. With that in mind, we’re going to present to you a balanced look at bare metal, RTOS, and OS to help you decide what might be the best for you. Let’s get into it.

What is Bare Metal Server?

A “bare-metal device” is a device that hosts an application.

In layman’s terms, it’s a physical device that is completely dedicated to running a single dedicated application, which for example, could be a “thermostat control program”. In the days before PCs, this was how computers worked. You booted one program at the time and only one single application could run at the time.

However, when your PC desk starts up today, it will typically boot up with Windows. Windows (or any other Operating System) is a program. An application is capable of loading, managing, and sharing the system resources (storage, CPU, network) to other applications (Word, Excel, games, browser, email programs, etc.). It does this in a way where these applications interfering with one another is minimal. This works well for a PC. Users expect to run multiple programs at the same time. That being said, this is not the only way to run applications.

For example, a thermostat program that measures the temperature via a sensor and turns on a heater when the temperature drops under a certain set temperature don’t need this level of complexity. In these circumstances, you might opt to use bare metal. This is because a device this simple doesn’t benefit from the overhead complexity that can occur from an RTOS (Real-Time Operating System) or OS.

Bare Metal vs. RTOS

The next stage up from a bare-metal system is an RTOS (Real-Time Operating System).

An RTOS has a relatively simple design, but, unlike Bare Metal, it can start and stop different processes concurrently. On the other hand, an RTOS is not as powerful as an OS. The most significant difference is usually memory protection and virtualization.

In a high-end operating system, application memory is separated, and the OS ensures that one process (running application) cannot corrupt the memory of another process. This is done by virtualizing the memory. This makes it possible for the OS to swap unused memory onto the disk when not used. Advanced memory handling is normally not present in an RTOS.

This level of advanced resource management (memory, disk, network, CPU) is very useful when applied on a general system like a PC, where you don’t know much about the application usage pattern. However, on small embedded devices, this is different. When operating such a device, you’ll typically have a good idea about:

  • How many applications/processes need to be running
  • What memory these applications/processes need
  • Making sure those processes don’t interfere with each other.

Therefore, when working with a small IoT device, developers normally chose an RTOS. This is because IoT devices have to manage a TCP/IP stack, which typically requires lots of context switches within the system. To avoid managing these complexities alone, applications that previously used bare metal and often moving towards RTOS or a fully-fledged OS. 

That being said, despite it being time-consuming, a lot of developers still prefer to put in the extra work. This is because the more it’s managed, the more you’ve got the ability to control things. So, while if you mess up, it’s your fault, at least you can get in there and make the amendments (something which is taken out of your hands when you use an RTOS or OS.). 

Want to find the right RTOS for your IoT device or application? Have a read of our IoT RTOS Comparison guide here.

Bare Metal vs. OS

Bare metal and an OS are at opposite ends of the spectrum. While Bare Metal and RTOS hold some similarities, such as reduced overhead, efficient memory usage – Bare Metal and OS have virtually none. 

You may be thinking that a traditional operating system is frowned upon by IoT developers and is simply too heavy for simple IoT devices. However, you’d be mistaken. General-purpose OS like Linux or Windows is still a viable option for IoT applications that require rich functionalities with powerful microprocessors, large memories, and run complex software. However, it’s more suitable to use OS for IoT gateways and cloud computing servers where there’s a need to process large data streams from various nodes or end devices.

One OS that is pretty renowned and widely used within the IoT community is the aforementioned Linux – which is often a fixture of embedded systems.

One such example of embedded Linux being used to operate a super, simple IoT device is the Raspberry Pi. The Raspberry Pi is a small circuit board that was originally designed for school children and to engage children in software development. To this day, it’s well respected within the IoT community and is often utilized in industries such as industrial IoT.

How Does Embedded Linux Work? Is It Good for IoT?

So, how does embedded Linux work? Well, applications are run over or supported by the kernel – acting as an operating system (OS). The “kernel” is the nucleus or core of the operating system and controls almost everything in the system. Therefore, every iteration between hardware and software goes through this kernel.

Embedded Linux or another type of operating system may seem like a good option for those looking for an out-of-the-box OS that’s easily scalable, requires less coding, and has community support.

However, the aforementioned kernel normally is distributed together with tons of supporting software that comes pre-installed. For the inexperienced developer, it can be hard to grasp which applications are actually running, what is their job, and do they possibly include a security danger (if used or configured incorrectly).

In the area of surveillance cameras, a lot of breaches have been found, not in the software made from the supplier but normally some found in the supporting software distributed with the operating system.

Are you still stuck on what the key differences between RTOS and OS are? Check out our blog – RTOS vs. OS – Advantages and Disadvantages.

Bare Metal vs. RTOS vs. OS: Comparison Table

As you can see, there are many advantages and disadvantages to every one of these solutions. Furthermore, the perceived pros and cons alter depending on what developer you ask.

Tricky, right?

To help better explain the differences between are metal, RTOS and OS, check out this bias-free comparison table below:

Bare Metal

RTOS

OS

Good for small devices

Level of application hardware control

Complete

Medium

None

Ability to multitask

Capable, but not with 100% separation

Overhead

None

Minimal

High

Efficient memory usage

Community support

Scalable/Portable

Medium

Easily portable

Bare Metal vs. RTOS vs. OS in IoT: The Verdict

We are not going to get drawn into this! The debate will continue to rumble on within the IoT community, and we only want to help you make an informed decision on what’s on this guide.

However, if you really want some insights, we will say this.

Bare Metal is great for IoT developers who want to remain in control of all aspects, have limited and small devices or applications, and have the knowledge to code and maintain the IoT stack themselves and really need the extra last resources squeezed out of minimal system hardware.

On the other hand, RTOS is a good option if you want minimal overhead with some resource management, but want a bit more community protection than the highly-culpable Bare Metal model.

Finally, an OS is good if you have a larger device and you are happy to “sacrifice” system resources and control but have the developing skills and capability to step in and identify any issues down the road. 

If you want to find out what we’d recommend for your device – get in touch with us today and book a free consultation.

Read Our Other Resources

We’ve also published a range of IoT resources for our community, including:

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