Custom RTOS vs Commercial RTOS vs Open Source RTOS


In the realm of embedded systems, Real-Time Operating Systems (RTOS) play a crucial role. These specialized operating systems are designed to manage resources and tasks with precise timing, ensuring reliable and efficient performance. Selecting the right RTOS for your embedded system is paramount to the success of your project.

There are three primary types of RTOS that developers can choose from: Custom, Commercial, and Open Source. Each type has its unique attributes and potential benefits, as well as drawbacks. By understanding the differences between these options, you can make a well-informed decision that best suits your project’s needs and requirements.

In this article, we will delve into the world of Custom, Commercial, and Open Source RTOS, examining their characteristics, advantages, and disadvantages. With the guidance of our professional, knowledgeable, and friendly team at RunTime Recruitment, you will be better equipped to make the right choice for your embedded system development endeavors.

Custom RTOS

Definition and Characteristics of Custom RTOS

A Custom RTOS is an operating system specifically tailored to meet the unique hardware and project requirements of a particular embedded system. It can be developed in-house by a company’s engineering team or outsourced to specialized companies with expertise in creating custom real-time operating systems. This bespoke approach ensures that the RTOS is optimized for the specific application it serves.

Advantages of Using Custom RTOS

Optimized performance is one of the main advantages of a Custom RTOS. By designing the operating system to work seamlessly with the specific hardware and project requirements, developers can achieve a level of performance that may be unattainable with off-the-shelf solutions.

Furthermore, intellectual property protection is another benefit of a Custom RTOS. Developing an in-house RTOS helps protect your proprietary technology from potential competitors, safeguarding your innovations.

Lastly, having a Custom RTOS grants complete control over system features and updates. You can decide when and how to implement changes, ensuring that your system remains up-to-date and aligned with your project goals.

Disadvantages of Custom RTOS

Despite its advantages, a Custom RTOS also has its share of drawbacks. High development and maintenance costs are often associated with creating a bespoke operating system, as you may need to invest in additional resources, personnel, and expertise.

Additionally, developing a Custom RTOS can result in a longer time to market for your embedded system, as the process of creating and fine-tuning the operating system may take more time than implementing an existing solution. Lastly, limited support and documentation can be a challenge with Custom RTOS, as there may not be a large community of users and developers to turn to for advice and troubleshooting.

Use Cases and Examples of Custom RTOS

Custom RTOS is often used in specialized applications where the unique requirements of the project or hardware necessitate a tailored solution. Examples of industries where Custom RTOS may be employed include aerospace, defense, and automotive systems, where performance, safety, and reliability are of utmost importance.

Companies in these sectors often have the resources and expertise necessary to develop a Custom RTOS that meets their exact requirements, ensuring optimal performance and protection of their intellectual property.

Commercial RTOS

Definition and Characteristics of Commercial RTOS

Commercial RTOS refers to operating systems developed and sold by established companies, often with a long track record in the embedded systems industry. These off-the-shelf solutions are offered with varying levels of support and licensing options, catering to a wide range of customer needs and requirements. Commercial RTOS is a popular choice among developers seeking a reliable, professionally-supported solution for their embedded systems projects.

Advantages of Using Commercial RTOS

One of the main advantages of choosing a Commercial RTOS is the professional support and documentation that comes with it. Established companies offering Commercial RTOS solutions typically provide extensive resources, training, and customer support to ensure that their clients can effectively implement and use their product.

Proven reliability and stability are also significant benefits of a Commercial RTOS. These operating systems have often been rigorously tested and refined over time, reducing the risk of unexpected issues and failures. Lastly, a faster time to market can be achieved with a Commercial RTOS. As these systems are ready to use, developers can focus on other aspects of their projects, accelerating the overall development process.

Disadvantages of Commercial RTOS

Despite its advantages, Commercial RTOS has some drawbacks. Licensing fees and restrictions can be a barrier for some projects, especially those with limited budgets. The costs associated with acquiring a Commercial RTOS and any necessary add-ons may be prohibitive for some developers.

Additionally, limited customization options can be a challenge with Commercial RTOS. While these systems are designed to be flexible and adaptable, they may not offer the same level of customization as a Custom or Open Source RTOS.

Finally, potential vendor lock-in can be a concern with Commercial RTOS. Once you have invested in a particular system and developed your project around it, it can be difficult and costly to switch to a different solution if your needs change or if the vendor discontinues support for their product.

Use Cases and Examples of Commercial RTOS

Commercial RTOS is commonly used in industries where reliability and professional support are highly valued, such as medical devices, telecommunications, and industrial automation. Examples of popular Commercial RTOS solutions include VxWorks, QNX, and Green Hills Integrity. These systems have been successfully implemented in a wide range of projects and applications, proving their reliability and effectiveness in the embedded systems market.

Open Source RTOS

Definition and Characteristics of Open Source RTOS

An Open Source RTOS is developed and maintained by a community of developers, who contribute their time and expertise to create a collaborative, shared solution. These operating systems are free to use, modify, and distribute under specific licensing terms, such as the GNU General Public License (GPL) or the Apache License. This collaborative approach offers a unique set of benefits and challenges compared to Custom and Commercial RTOS options.

Advantages of Using Open Source RTOS

One of the primary advantages of an Open Source RTOS is the absence of licensing fees. Developers can access and use these systems without incurring any costs, making them an attractive option for budget-conscious projects. Active community support and collaboration are also significant benefits of Open Source RTOS.

The community-driven development model fosters a wealth of knowledge and resources, enabling developers to learn from each other and tackle common challenges together. Moreover, a high level of customization can be achieved with Open Source RTOS. As the source code is freely available, developers can modify and adapt the system to their specific requirements, creating a tailored solution without the costs associated with Custom RTOS development.

Disadvantages of Open Source RTOS

Despite its benefits, there are some disadvantages to using an Open Source RTOS. Limited professional support can be a challenge, as the community-driven nature of these systems means that dedicated customer support and resources may not be readily available.

Potential legal and intellectual property concerns may also arise with Open Source RTOS, as the licensing terms and conditions can be complex and may require careful consideration to ensure compliance. Furthermore, the reliability and stability of Open Source RTOS may vary, as the quality of the code and its maintenance can depend on the commitment and expertise of the contributing developers.

Use Cases and Examples of Open Source RTOS

Open Source RTOS is often used in projects where cost savings, community collaboration, and customization are key priorities. Examples of popular Open Source RTOS solutions include FreeRTOS, Zephyr, and RIOT. These systems have been implemented in a wide range of applications, such as IoT devices, consumer electronics, and robotics, proving their versatility and adaptability in the embedded systems domain.

Factors to Consider When Choosing an RTOS

Project Requirements and Constraints

When selecting an RTOS for your embedded system project, it is crucial to consider the specific requirements and constraints of your application. System performance is a key factor, as the chosen RTOS must be capable of meeting your project’s demands in terms of processing power, memory usage, and real-time responsiveness.

Hardware compatibility is another essential aspect to consider, ensuring that the RTOS will work seamlessly with your chosen hardware platform. Lastly, your development and maintenance budget will play a significant role in determining which RTOS is the most viable option, as costs can vary widely between Custom, Commercial, and Open Source solutions.

Support and Documentation

The availability of technical resources, such as documentation, tutorials, and example code, is an important factor to consider when choosing an RTOS. Comprehensive support materials can greatly facilitate the development process and help you avoid potential pitfalls. Furthermore, the level of community or professional support available for your chosen RTOS can significantly impact your experience, as having access to knowledgeable experts and fellow developers can be invaluable when troubleshooting issues or seeking guidance on best practices.

Licensing and Legal Considerations

Intellectual property protection is an essential consideration when selecting an RTOS, particularly for projects involving proprietary technology or innovations. Ensuring that your chosen RTOS offers suitable protection for your intellectual property can be critical to your project’s success.

Additionally, it is crucial to understand the licensing terms and conditions associated with your chosen RTOS, as these can impact your ability to modify, distribute, and commercialize your product. Comparing the pros and cons of open source versus proprietary licensing terms will help you make an informed decision that aligns with your project goals and legal requirements.


In this article, we have explored the differences between Custom, Commercial, and Open Source RTOS, highlighting their unique characteristics, advantages, and disadvantages. Each RTOS option offers specific benefits and challenges that must be carefully considered when choosing the best solution for your embedded systems project.

The importance of thoroughly evaluating your project requirements and the available RTOS options cannot be overstated. By taking into account factors such as system performance, hardware compatibility, support, and licensing, you can make an informed decision that best aligns with your project’s goals and constraints.

Our team at RunTime Recruitment is here to help you navigate the complex world of RTOS selection. With our professional, knowledgeable, and friendly approach, we can provide guidance and expertise to ensure that you choose the best RTOS for your specific project. Get in touch with us today to leverage our extensive experience in the field of engineering recruitment and make the most of the benefits that the right RTOS can bring to your embedded systems development endeavors.

Hire Highly-Skilled Engineers with RunTime Recruitment

Our expert team of engineers-turned-recruiters offers in-depth technical recruiting knowledge in the engineering industry.

If your company is looking to recruit highly-skilled engineers worldwide, contact us today and we will do the sourcing for you. Or if you’re an engineer looking for new opportunities, you can check RunTime Recruitment’s job site for job vacancies.

Recruiting Services