What Is
Embedded Linux?

Your guide to Linux for embedded systems. Learn about the differences between embedded Linux distributions and how to choose the right one.

 

What Is Embedded Linux?

Embedded Linux is built on the same Linux kernel, available from kernel.org, as all Linux systems. But embedded systems have tight constraints that enterprise systems simply don’t have, ranging from higher reliability and security requirements to tighter resource availability and the need for engineering support that often lasts 10 years or more. Furthermore, embedded devices usually need to communicate with each other and with cloud resources.

Linux for embedded systems, then, requires additional packages beyond the original kernel. Which specific packages are required for your distribution depends on what you are going to build, and the best solution will differ for different use cases. Ultimately, each embedded Linux system is unique, purpose built for the intelligent edge.

Embedded Linux is an open source operating system that is purpose built for the intelligent edge.

Open Source Foundational Principles

Linux developers must follow these three foundational principles for all open source software and tools:

Collaborate: Share code, review others’ code, contribute to fixes and patches, write documentation, and participate in discussion boards and mailing lists.

Innovate: Adapt and adopt new technologies.

Comply: Review regulatory standards and licenses, including license compliance and license contamination.

Embedded Linux offers developers several advantages over other OSes

Embedded Linux Advantages

Embedded Linux offers developers several advantages over other operating systems:

  • Cross-compilation for any supported platform
  • Community reflection of Common Vulnerabilities and Exposures (CVE) fixes in updated releases
  • Deployment to commonly used Linux infrastructure and tools
  • Modern, cloud-native environment
  • Broad hardware support
  • Product lifecycle through community LTS

Hardware Needs for Embedded Systems

Embedded devices are restricted by environments that generally dictate low power consumption, reduced processing power, memory limitation, and peripheral availability by design. There are a multitude of hardware architectures, including x86, Arm, PPC, and RISC-V, each having their own advantages and limitations (such as low power consumption and limited software support).

Embedded Linux Architecture

At the most basic level, an embedded Linux system is one that uses Linux as the operating system that sits between the hardware and the application of an embedded device. There are five key components to an embedded Linux system:

  1. Hardware processor
  2. Hardware abstraction layer (HAL)
  3. Linux operating system
  4. Service layer
  5. Application layer

Components of an Embedded Linux System

Embedded Linux Development

BSP Development

A board support package (BSP) is a layer of software containing hardware-specific drivers and other routines that allow Linux to function in a particular hardware environment. It should be customized not just to the correct architecture/OS combination but down to the exact system-on-chip (SoC) and board configuration. To optimize an embedded environment, the BSP should also include a customized version of Linux (or another OS). Your BSP vendor can provide customized test suites, developer assistance from experts, and other professional services.

System Integration

An aggregation of subsystems cooperates so that the system can deliver overarching functionality and ensure that the subsystems function together as a system. System integration involves coordinating existing, often disparate, embedded systems so that the specialized use case can be addressed.

Types of Linux Distros for Embedded Systems

There are a bewildering variety of flavors of Linux distributions — some built for enterprise use, some specifically for embedded; some from the open source community, some supported commercially; some that are provided as part of a package with hardware, some that are developed in-house — and all these categories can overlap.

Embedded Linux Distro Examples

Embedded Linux Enterprise Linux
Hardware Vendor Linux Community Embedded Commercial Embedded Commercial Enterprise Community Enterprise Roll-Your-Own
  • Customer ready and usually delivered as an SDK focused on hardware-specific features
  • Free to use, as an enabler for hardware sales
  • May contain proprietary components that were not upstreamed
  • CPetaLinux (Xilinx)
  • Yocto Project (OpenEmbedded)
  • Buildroot
  • OpenWrt
  • Linaro Arm
  • Wind River Linux
  • Mentor Embedded Linux (FlexOS)
  • Mentor Embedded Linux (OmniOS)
  • MontaVista CGX (Carrier Grade Express) Linux
  • Ubuntu Core
  • Red Hat Enterprise Linux
  • SUSE Linux Enterprise
  • Ubuntu Server (Canonical)
  • Fedora
  • CentOS
  • openSUSE
  • Ubuntu
  • Debian
  • Developed in-house, using free and open source components (fork of the community work)
  • Can start with a silicon vendor SDK or be based on enterprise Linux distributions (e.g., Ubuntu, Fedora, CentOS) or embedded Linux projects (OpenWrt, Buildroot, Yocto Project)

Roll-Your-Own Linux

“Roll-your-own” or RYO Linux refers to a Linux distribution that is developed and customized in-house using free and open source components. Three of the most important and popular open source components used to build RYO Linux distros are the Yocto Project, Buildroot, and Raspberry Pi.

Yocto Project

The Yocto Project was created to standardize the platform for embedded Linux, thereby enabling interoperability and extensibility for an ecosystem of hardware and software vendors working with a common set of standards and tools.

BuildRoot

Buildroot is a simple tool that generates embedded Linux systems through cross-compilation. (For example, you can use an existing cross-compilation toolchain and build only your root file system with Buildroot.)

Raspberry Pi

Raspberry Pi is a free operating system based on Debian and optimized for Raspberry Pi hardware. Raspberry Pi Imager provides a quick and easy way to install Raspberry Pi OS and other operating systems to a microSD card, ready to use with your Raspberry Pi.

Enterprise Linux

The general-purpose server and desktop Linux distributions from Red Hat, Ubuntu, and others are intended for well-resourced, multipurpose, and often multiuser solutions and are typically configured to support a wide range of devices. Supported customizations are usually limited to package installation and configuration files. The results are a solid user experience, reliability suitable for general-purpose use, and an inexpensive support model for three to five years. However, off-the-shelf enterprise Linux is usually a poor choice for embedded systems: It is resource intensive, has a large attack surface, and offers short maintenance windows .

Enterprise Linux vs. Embedded Linux
Enterprise Linux Embedded Linux
  • These are truly general-purpose operating systems, not built for single-purpose use for a specified device.
  • The OS vendor handles the design and compilation of the OS environment.
  • The user is limited to selecting a configuration or edition, installing additional software packages, and handling the administrative configuration of individual items.
  • Everything is expected to be used in a purely binary environment by IT staff and general users.
  • Distributors often include long-term support for only certain common components, such as unmodified software, and common usage considered typical for the platform in use cases with relatively short product lifecycles (three to five years).
  • These are special-purpose systems, often with specific capabilities and no direct interaction with the end user.
  • System design constraints resulting from limited hardware and memory necessitate customizations and software built from source code.
  • The system is built into critical infrastructure, and the economics of customization, reliability, and other design requirements drive higher costs that need to be spread over a longer lifecycle, usually five to 10 years or even beyond.

Commercially Supported Embedded Linux

Commercially supported embedded Linux boasts advantages that are similar to those of enterprise Linux. With specific use cases in mind, most commercially supported embedded Linux vendors create a compact core that supports low-resource or resource-constrained environments, greater security requirements, high performance and reliability needs, and a build system that requires only local support for extensions. The approach is not a one-size-fits-all distribution. Commercially supported Linux offers strong support and maintenance over the product lifecycle, leading to desirable savings. However, this solution also offers the ability to customize the platform, speed development, and get to market faster.

Community vs. Commercial Linux

Community and commercial Linux distributions are mutually inclusive. Every major commercial distribution has a free open source variant from the community based on and used for upstreaming content. Technology investment (such as that from the Linux Foundation) or commercial investment backs the various communities that produce these variants.

Community Linux Commercial Linux
  • Contemporary successful projects are based on open source technologies and community innovation.
  • Every open source community is different but follows a similar organizational structure, with leaders, maintainers, contributors, and users.
  • Various levels of participation are available, given the need for technical contributions and governance activities.
  • The focus is on innovation (update/upgrade) — “stable” releases with little or no focus on long-term support.
  • The approach to defect fixes and CVEs is reactive.
  • Each distribution is created and backed by a single commercial entity.
  • The initial focus is on leveraging community innovation into a commercial-quality product, with secondary focus on long-term support and maintenance (usually covering between five and 10 years).
  • Risk in terms of open source licensing and policy management is reduced for overall Linux adoption and mitigation.
  • Service-level agreements provide clear targets.
  • The approach to defect fixes and CVEs is proactive.

How to Choose the Right Linux Distro

There is no one distro to rule them all, but Linux is extremely versatile and brings power to the use cases it is deployed for. Server and cloud infrastructure platforms, together with workstations, rely on general-purpose distributions, whereas embedded devices and systems are specialized and purpose built. It is difficult to find a distribution for embedded solutions, so you may need to rely on a distribution builder to tailor your solution. Below are challenges and capabilities to consider when choosing a Linux distro and building a solution.

Business Challenges to Address

Enabling the full stack for modern applications and use cases

Enabling the full stack for modern applications and use cases

Meeting performance and reliability requirements

Meeting performance and reliability requirements

Providing the latest industry-specific features and standards

Providing the latest industry-specific features and standards

Preparing for compliance and export audits

Preparing for compliance and export audits

Continuously staying ahead of potential security breaches

Continuously staying ahead of potential security breaches

Risk Reduction

  • Maintenance, including CVE monitoring and fixes
  • Support, including resolution of build and other technical issues
  • Repeatable build process
  • License compliance and bill of materials
  • Documentation and community mailing list
  • SDKs provided by silicon vendors

Flexibility

  • Ability to create your own purpose-built embedded Linux OS
  • Flexibility to use a binary or source-based Linux release
  • Open source OS innovation with no vendor lock-in
  • Available and free to use with proper license compliance
  • Full source code included

Solution Development Speed

  • Access to a customized, purpose-built Linux for embedded applications
  • Sustained innovation with periodic releases and a long-term stable option
  • Wide range of BSPs available through hardware vendor SDKs
  • Support for standard and preempt_rt real-time Linux kernels

Build vs. Buy

Although it may seem counterintuitive, over the lifecycle of the product, proven commercial embedded Linux with support and maintenance tends to be much less expensive than maintaining a roll-your-own Linux solution in-house. It is difficult to predict the cost of creating and maintaining a large, complicated RYO Linux system, and it is expensive to support, patch, and manage security vulnerabilities in an ongoing fashion. The bottom line is that the cost will be considerable and that it is easy to underestimate it, especially if your organization is new to embedded development, deployment, and servicing.

Total Cost of Ownership (TCO)

“Roll-your-own” Linux distributions offer the up-front appeal of control and perceived price efficiency. However, unexpected consequences can include the following:

  1. As products mature in the field and new generations of products are released, the effort required to manage and maintain open source increases significantly.
  2. More staff are needed to sustain multiple versions and check for security vulnerabilities and exposures in each release.
  3. Companies that do not prioritize maintenance and modifications can end up with custom “forked” versions that require years of maintenance.
  4. Many organizations are unaware of the compliance obligations for shipping solutions based on Linux.

RYO Linux is inexpensive in the beginning, but costs rise steeply over time.

KEY COMMERCIAL BENEFITS
  • Time-to-market: Start with code that was pre-validated for your commercial use case, instead of building from scratch.
  • BSP development: Ensure that hardware peripherals are well supported and optimized for your deployment.
  • Hardware optimization: Architect your solution based on commercial off-the-shelf (COTS) or custom hardware, considering resource constraints such as disk space or boot time.
  • Streamline development: Accelerate feature development and design with professional services.
  • Long-term savings: Evaluate the total cost over the entire lifecycle of the deployed device and choose a commercial vendor who leverages economy of scale to provide cost-effective support and maintenance.
  • Compliance and export artifacts: Rely on pre-generated artifacts to comply with regulatory requirements for your deployment worldwide.
  • Continuous delivery/continuous integration (CI/CD): Stay current with the latest innovations by continuously improving your device through updates and fixes, ensuring long-term operational capability.
  • Premium support SLAs: Rely on industry experts, available to address your issues 24/7, with strict terms for delivering fixes and support.
  • Linux security: Make sure you build the highest level of security for your device according to your deployment use case, making security part of your development, deployment, and operational processes.
  • Development tools: Leverage tools that streamline your processes and help your engineering team achieve goals on time and on budget.
  • Community leadership: Count on the expertise of community leaders who can influence the direction of open source projects from strategic and technical perspectives.

How Can Wind River Help?

Wind River Linux

Wind River® provides the industry’s most advanced embedded Linux development platform, with a comprehensive suite of products, tools, and lifecycle services to help our customers build and support intelligent edge devices in segments such as aerospace and defense, industrial, medical, automotive, and more.

Linux-based edge devices and systems offer less risk and development effort compared to RYO in-house efforts. Wind River provides an offering to keep your code base up-to-date, track and fix defects, apply security patches, and customize your runtime to adhere to strict market specifications and certifications. Additionally, Wind River can facilitate your IP and export compliance and significantly reduce your costs.

For 40 years, Wind River has been the global leader in the embedded software industry, with decades of expertise, more than 15 years as an active contributor and committed champion of open source, and a proven track record of helping customers build and deploy use case–optimized devices and systems.

Wind River Linux runs on hundreds of millions of deployed devices worldwide, and the Wind River Linux suite of products and services offers a high degree of confidence and flexibility for prototyping, developing, and moving to real deployment.

>>  Learn more

Wind River Professional Services

Success in a competitive market means concentrating on what you do best — building great products for the industries you serve. Wind River offers services that allow you to avoid the risk and expense of developing platforms that, while necessary, don’t actually add to your feature set.

  • North America
  • Ottowa, Canada
  • Dublin, OH
  • Alameda, CA
  • Detroit, MI
  • Costa Rica
  • South America
  • Cordoba, Argentina
  • (C/E Services Only)
  • Europe
  • Stockholm, Sweden
  • Paris, France
  • Munich, Germany
  • Galati, Romania
  • China
  • Chengdu, China
  • Beijing, China
  • Korea
  • Seoul, Korea
  • Japan
  • Tokyo, Japan
  • Nearly 400 experienced engineers
  • Average developer with 5+ years cross-vertical industry experience
  • Global network of experienced architects
  • Balanced cost structure to deliver quality of service and affordability
  • Time zone–aligned development
  • Round-the-clock capability
  • CMMI level 3 and A-Spice development
  • 95% English speaking
  • Concept, prototype and mass production development experience
BSP DEVELOPMENT

Wind River offers an expansive list of board support packages (BSPs), software kits that provide a layer between the hardware architecture and the operating system. Our Professional Services team can also design and develop a custom BSP for your project, including acceptance tests for features that are specific to your hardware.

>>  Learn more
Frozen Branch Services

Frozen branch services provide configuration management, security monitoring, and maintenance specific to a customer-designated version of Wind River Linux for all phases of the Wind River Linux product lifecycle. Customers are informed of patches that are available for the platform and may select those they want incorporated, thereby minimizing revalidation costs.

Services for the platform include:

  • Providing monthly notifications to customers of potential security errors, with available patches
  • Backporting and integrating customer-selected security patches with the customer-designated version of Wind River Linux
  • Addressing errors reported by the customer and creating a patch if needed for the customer-designated version of Wind River Linux
  • Testing patches for the customer-designated version of Wind River standard Linux on one Wind River Linux BSP and reference board
  • Releasing patches that were integrated into the customer-designated version of Wind River Linux
Custom Content Maintenance (CCM)

CCM service provides configuration management, security monitoring, and maintenance specific to a customer’s platform, including the open source packages that were added on top of Wind River Linux. Customers are informed of patches that are available for the platform and select those they want incorporated. The package is renewable yearly, but the price is subject to change each year. Services for the platform include:

  • Fixing bugs as reported and requested by the customer, in customer-specific open source packages
  • Notifying the customer of potential patches available for all the open source packages in their platform
  • Backporting and integrating customer-requested bug fixes provided by Wind River Engineering on the current Wind River Linux release
  • Monitoring for security patches to customer-specific open source packages, notifying the customer of available patches, and integrating those selected by the customer
  • Backporting and integrating customer-selected security patches provided by Wind River Engineering on the current Wind River Linux release
  • Testing patches using the test suite for the version of Wind River Linux in the platform on one Wind River standard product BSP and reference board
  • Releasing patches that were integrated into the platform to the customer

Security

Wind River addresses security on many levels:

  • CVE monitoring, assessment notification, and remediation
  • Inclusion of many common security packages in our distribution
  • Regular updates that include security fixes
  • OS hardening and cybersecurity capabilities, including Linux kernel hardening and allowlisting

*As of the end of Q3 2021, Wind River CVE Database

Embedded Linux FAQs

Embedded Linux is the operating system purposely built for the hardware it enables, in an embedded system or device architected for a specialized use case.
Embedded Linux is used to power purposely built hardware for specialized use cases.
No, embedded Linux is not an RTOS. However, for systems that require determinism, preempt-rt patches to the Linux kernel can provide similar functionalities with comparable performance.
Linux, in general, is associated with the enterprise operating system used for workstations and servers, while embedded Linux is used for purpose-specific devices and systems.
Yes. Raspberry Pi OS (formerly Raspbian) is a good example of an embedded Linux variant, based on Debian distribution and enabled for Raspberry Pi hardware.
Linux is the most popular choice for embedded development, due to its wide adoption in this space and its community-driven innovation.
Embedded Linux starts at the lowest level of functionality required for a simple device to execute various tasks and its application in an environment with limitations (such as processing power or memory usage and constraints such as safety requirements or extreme weather).
Embedded Linux OS examples include but are not limited to Ubuntu Snappy or Raspberry Pi OS, but they can also be built with embedded distribution builders such as Yocto Project or Buildroot.
Linux kernel is evolving based on a large community of developers, so the latest is always the greatest. But, since it is hard to keep up with the continuous innovation delivered by the community, the best recommendation is to start with an LTS (long-term stable) version.
There is no one distro to rule them all, but Linux is extremely versatile and brings power to the use cases it is deployed for. For servers and cloud infrastructure, the leader will be Red Hat or CentOS, while for embedded the leader is Wind River Linux.
Linux is the most popular development platform for embedded applications due to its wide range of capabilities and extensive embedded hardware support.
No, Yocto Project is not a Linux distribution but a set of tools that can help build an embedded distribution, using reintegrated ingredients such as packages, recipes, and meta data from OpenEmbedded.
Bare metal refers to the capability of software running on and accessing direct hardware resources, without the need for an operating system to manage this process.
It is important to understand the requirements of your embedded device and then figure out the bill of materials necessary to achieve the project goals. The next step is to choose the hardware, then select the OS that with a board support package (BSP) for the specific hardware and capabilities required.
Embedded is purpose built, so your project’s version, with its customizations, will be best for your embedded use case.
Compared to general-purpose Linux, it is harder to build a Linux-based OS for embedded, because you need to start with a clear set of requirements, understand the constraints based on the use case you are addressing, and consider the maintenance aspects over the lifecycle of the device.