Embedded Linux: What It Is, When and How to Use It

Embedded operating systems are old news in the tech market, and engineers have developed dozens of them to facilitate hardware and firmware development. Because of this, we can now choose the best, utilizing those that went through thick and thin and have proven to be the best for engineering purposes. Since embedded systems are designed for narrowly-targeted functionalities, it's paramount to understand which tools for their development will fit all your requirements. 

So, what is embedded Linux, and why has it become such a buzzword in the silicon-keen world?

Embedded Linux includes a Linux kernel operating with the help of open-source software development tools and fundamental GNU utilities. Its baseline advantages for developers are readymade pieces of code they can incorporate into their embedded apps. They no longer have to work with cold and empty hardware, developing everything from scratch. 

Thus, embedded development has shifted from the overly complex, which made engineers' blood run cold, to a quick and much less painful process. Also, the fact that Linux supports multiple software variants required for creating embedded apps, such as serial communication protocols, TCP/IP stack, etc., makes embedded Linux impossible to resist. 

For this article, we asked LS embedded engineers to shed some light on embedded Linux development services, including their advantages, disadvantages, differences between Linux and embedded Linux, and its main applications.

Differences between embedded Linux and Linux

Before we get started with a deeper analysis of the embedded Linux system, let's first consider how it differs from Linux. 

Linux components:

• OS Kernel 
• Bootloader
• Background services or “daemons” in Linux
• Graphics server
• Desktop environment. In Linux, there's no direct interaction with the graphical server. The desktop environment helps with this via Cinnamon, KDE, and Unity 
• Applications

Embedded Linux components:

• Cross development toolchain, including the GNU debugger (GDB), the GNU compiler collection (GCC), and C libraries. These toolchains are integrated into embedded Linux because an embedded processor for specific devices usually cannot sustain these toolchains.
• Bootloader — Uboot and barebox for embedded Linux.
• Linux Kernel
• Device Tree keeps data about the connected hardware devices that is not detectable. 
• The root file system in Linux arranges data into directories and organizes files in the storage device. In Linux, the information is stored in the form of files and stores, and is also accessed through a file.
• System Programs
• Applications

As you can see, there are a number of common characteristics between embedded Linux and Linux. Now, let's see what features they don't share.

Main points you should know about Linux:

• You can use it on general-purpose computers
• It requires BIOS/UEFI boot support
• It works on x86 and x64 processors
• Linux requires extensive hardware support

Now, to the embedded Linux core peculiarities:

• It is applied with special-purpose computers
• Embedded Linux only requires the hardware support necessary for the embedded device you want to develop
• It has a low power consumption
• There is no need for BIOS/UEFI support
• It usually runs on ARM processors

As you can see, these technologies are primarily designed for different purposes. That's why you should bear in mind their requirements as you choose the appropriate one for your project.

Why embedded Linux?

So, which features of embedded Linux make it the first thing that comes to engineers' minds when they are tasked with building a convenient embedded system?

1. Linux is an open-source OS which allows for the addition or elimination of any components you wish. 
2. Multiple code parts are free to use, so you will save costs on the embedded development of your device.
3. It ensures the high speed of product development due to the availability of a readymade TCP/IP stack, Linux Kernel, SPI libraries, graphics libraries, and many more features.
4. It runs on such processors as ARM (widely used in diverse apps), MIPS (apps used for networking purposes), X86 (usually needed for industrial apps), and SH (multimedia apps). Concerning RAM memory, its use is variable in each individual case of embedded system development. You can also use it on Raspberry Pi boards, which are relatively low-priced.
5. There are numerous software and support providers for embedded Linux.

All the listed advantages of embedded Linux ensure substantial flexibility for embedded engineers and business owners who search for reasonably priced project development.

Embedded Linux use cases

Due to the scalability of the Linux operating system and its ability to work on multicore processors, business owners who want to develop complex applications can be sure that the embedded Linux system will easily handle them. This embedded software supports apps that require multiple threads with parallel performance. Thus, you can easily employ embedded Linux for data processing apps. Its reliability is so high that even aerospace engineers prefer it for complicated and power-consuming spaceship and satellite firmware.

There's another area where embedded Linux has proved to be a reliable and highly effective tool to use — AI-based apps. The development of ML models requires accuracy and stability in data analysis and the resulting output. But with embedded Linux, your app with deep neural networks and other complex ML algorithms will work smoothly. As a rule, embedded engineers use different types and versions of single-board computers for numerous types of AI projects.

In general, embedded Linux serves narrowly-targeted systems with a specific set of functionalities. For instance, you can apply it to consumer electronics devices like smartwatches or smart speakers, or industrial technologies that maintain surveillance, networking apps for routers, and many more. This technology is ubiquitous and has numerous methods of applications. 

At Lemberg Solutions, we have turned to embedded Linux development even for the most complex projects. One of them was to refactor code for bioprinters belonging to a Swedish bioconvergence startup — CELLINK. Another example was the development of a sportstech device owned by Speede, an American fitness startup, which was designed for more effective workouts. We used Raspberry Pi boards with embedded Linux in both cases.

Complications caused by embedded Linux

Despite substantial advantages inherent to embedded Linux, there are specific pitfalls you will face while using it. 

First of all, embedded Linux is quite a complex system due to the high number of contributions made to its open-source code. Even though you might be used to the Linux kernel, developers add multiple features and refinements, making embedded Linux software development not only applicable to the biggest number of projects possible but also extensive and hard to catch up with. 

On top of that, if you implement any modifications into your hardware, expect it to affect the software as well. That's why engineers should be aware that changes in the embedded device will cause the software to be reworked or the hardware components to be replaced. Embedded Linux also requires more memory space as opposed to other embedded development tools. 

Taking into account these complexities, the project can take more time if you decide to integrate certain changes into your device in the future. That's why it is often better to choose a third-party partner with extensive embedded Linux development experience, ensuring it is less painful for you to develop and improve your device.

Buildroot for embedded Linux

Buildroot and Yocto Project (which we discuss later) were designed to facilitate the development of custom embedded systems using the Linux operating system. In this part of the article we explain what perks you can get from applying them to your embedded projects. 

Buildroot is an easy-to-understand and practical tool to develop embedded Linux systems by means of cross-compilation. It is designed as a simple technology that speeds up the embedded development process. Buildroot mainly deactivates extra compile-time settings for all packages, making the system concise and effective. But embedded engineers working on a specific system can still enable the settings necessary for a specific device's performance.

Buildroot assembles all components from the source. However, this tool doesn't ensure the target package management. Overall, the images in Buildroot are established during its build time. It is written in Make, and its size is quite small, so embedded engineers don't need to go through the Minotaur maze to master the whole system. 

At the same time, Buildroot is scalable and developers can have a field day integrating features into its embedded Linux. The tool was created to manage basic use cases, but embedded engineers can expand the code. Buildroot runs on Kconfig language (created by the Linux kernel community) and Makefiles.

What about Yocto Project?

Yocto Project contains metadata and cross-platform tools that allow engineers to develop customized Linux distributions swiftly while using source code. Yocto facilitates the software development process, making the embedded Linux experience better. In contrast to a full Linux distribution, the system, customized to your requirements, saves necessary software to ensure it is narrowly focused on your embedded app requirements. Yocto Project is beneficial in the development of systems and applications, management, and archiving. Engineers can adapt their systems for memory footprint and speed. On top of that, they can easily enable software customization for different hardware types and preserve the scope of the software stack.

This open source project ensures considerable flexibility. For instance, if undertaking projects of an enterprise scale, engineers can modify Linux Distros to their needs by leaning on basic actual special Linux systems and using them in numerous end products. Applying Yocto in embedded development leads to decreasing the customization complexities of diverse Linux Distros improvements and lessening the troubles connected to cross-architecture migration.

The takeaway

You made it to the end of the article, and it's time to recap and recollect the main points we’ve made. Even though embedded Linux is at first a complicated topic to grasp, you should remember that it suits an enormous amount of engineering needs. With embedded Linux, you can develop a highly customized app without the need to create every single feature from scratch, which is a big advantage, especially in the modern world of stringent deadlines for technological progress. That's the main difference between embedded Linux and Linux, since in the first case you can use it for narrowly targeted purposes, while the latter it is applied on general-purpose computers. Additionally, embedded Linux has low power consumption, which is especially beneficial for embedded devices running on batteries. Being an open source OS, embedded Linux allows for a high speed of product development. It also works efficiently on multicore processors and can easily handle even the most complex apps. That's why embedded Linux is even used in aerospace tech development.

If you have an IoT development services project in mind and need to rely on a tech partner who can help you get through all the complexities of embedded development, don't hesitate to contact us.