Best Real Time Operating System in 2024

Summary: This comprehensive guide offers valuable insights into real-time operating systems (RTOS), providing essential knowledge for anyone navigating the selection process. Let’s understand what exactly RTOS are, its types, characteristics and top real-time operating systems in the market. 

What are Real-Time Operating Systems?

A Real-time Operating System (RTOS) is a specialized operating system that is designed to manage hardware resources and execute external events within strict time constraints. RTOS plays a pivotal role when it comes to performing tasks like controlling a medical equipment or guiding a spacecraft. So, while performing such critical tasks, you need a real-time operating system that can get these things done precisely on time. Overall, RTOS acts like a heart that can’t skip a beat. 

Unlike general-purpose operating systems, which prioritize maximizing throughput and resource utilization, RTOS focuses on minimizing task response times and managing deadlines.  

RTOS generally focuses on two things- determinism and predictability. Determinism in RTOS guarantees that tasks are completed within a specific time window, every single time they run. It ensures that the system works precisely and rapidly with no room for delays. Whereas predictability ensures that the time it takes for a task to run should be the same each time, regardless of other activities happening in the system. 

What is a Real-time Operating System Used for? 

Real-time operating systems (RTOS) are used in devices where the assigned task must be completed within strict deadlines. This is crucial for systems where delays can cause malfunctions or even safety hazards. RTOS can be used in the following devices: 

1. Air traffic control systems 
2. Airbags and antilock brakes 
3. Cameras 
4. Medical applications and systems 
5. Telecommunication and routers 
6. Industrial control systems, and more 

Types of Real-Time Operating Systems 

There are three main types of real-time operating systems (RTOS): Hard RTOS, Soft RTOS, and Firm RTOS. Each type is suited for different needs based on the level of determinism required: 

1. Hard RTOS: This type of RTOS offers the strictest guarantees on timing constraints. It makes sure that tasks must be completed within a deadline every single time. For example, suppose a medical institution needs a special system to control important machines like ventilators. Hard RTOS make sure these machines always respond on time. This is important because if they don't work on time, it could put the patient's life at risk. 
2. Soft RTOS: Soft RTOS offers more relaxed timing constraints compared to hard RTOS. While it still prioritizes timely task completion, occasional deadline misses are tolerable if they don't significantly impact system functionality. For example, Multimedia systems (e.g., video conferencing, streaming) Telecommunication systems (e.g. data transfer), and more. 
3. Firm RTOS: Firm RTOS falls somewhere between hard and soft RTOS. It provides some level of guaranteed deadlines, but with more flexibility than hard RTOS. Missing deadlines in a firm RTOS may degrade system performance but won't cause complete failure unlike Hard RTOS. Some examples include process controls systems, traffic controls, financial forecasting systems etc. 

How to Choose the Best Real-Time Operating Systems for Your Device?

Before selecting a real-time operating system for a device, users must look for their budget, accessibility, compatibility and more. Here are some of the factors to consider while choosing the best Operating Systems for your device:  

• What type of RTOS you need: The first step is to understand what type of RTOS you need (Hard vs. Soft vs. Firm Real-time). This is the most crucial factor, so analyze your application's needs carefully. Does it require guaranteed deadlines with zero tolerance for misses (hard RTOS)? Or can it handle occasional misses (soft RTOS)? Perhaps a balance between the two is ideal (firm RTOS). This will help you narrow down the options to choose an OS that best suits your usage patterns and preferences.  
• Device compatibility: RTOS generally varies in terms of resource usage. So, check if the chosen real-time OS aligns with your device's hardware specifications and supports the software applications you need. It is important to note that compatibility issues can hinder the functionality of your device.  
• Security: If your device handles sensitive data, evaluate the RTOS's security features like memory protection and user authentication, and how they align with your security requirements. 
• Scalability: Scalability is crucial when selecting RTOS for your device. Ensure the RTOS can accommodate future hardware upgrades seamlessly. This ensures your device remains compatible and efficient as it evolves, saving time and resources on potential system overhauls. If you plan to upgrade your device's hardware in the future, consider RTOS that can scale accordingly. 
• Cost: Lastly, understand the RTOS's licensing model (open-source, commercial, royalty-based) and its implications for your project's budget and distribution rights. Consider the cost of development tools, potential code size limitations of the RTOS, and any ongoing royalty fees associated with the license. 

Characteristics of Real-Time Operating Systems 

Real-time operating systems (RTOS) are resource efficient, lightweight, and use real-time scheduling algorithms. Here are some key characteristics: 

1. Lightweight: RTOS are often smaller than general-purpose OS. This makes them suitable for devices with limited memory resources. 
2. Real-Time Scheduling Algorithms: RTOS uses specialized scheduling algorithms that prioritize tasks based on their deadlines. This ensures that critical tasks are processed first and completed on time. 
3. Better Performance: Compared to general-purpose OS, RTOSs are designed to be fast. They focus on handling critical tasks quickly with minimal add-on processes running in the background. 
4. Resource Management: RTOS manages system resources such as CPU time, memory, and peripherals efficiently to meet real-time constraints. Resource allocation strategies prioritize critical tasks while preventing resource contention. 

Top 10 Real-time Operating Systems Comparison 

Here is a comparison table of the top real-time operating systems along with their key features and pricing plans.

Best Real-time Operating Systems
Softwares	Features	Real-time Operating Systems Pricing
Azure RTOS	Easy task scheduling, Synchronization and memory management, Enable runtime stack checking, Priority inheritance, Deterministic processing, Performance and driver management	Available on request
embOS	No interrupt latency, Less memory usage, Core written in assembly language, Real time kernel viewer (embOSView), Minimum RAM usage, High performance	Starting at $6300 (approx.)
TI-RTOS	Provides deterministic preemptive multithreading, Interrupt handling and memory management, IPv4 and IPv6-compliant, Supports time-triggered functions, Synchronized data exchange	Available on request
Integrity RTOS	Works on hardware memory protection, Secure partitions, Respond to events in nanoseconds, Memory-resource protection, Minimum latency, Advanced Multicore Support	Starts at $15,000
LynxOS	Multi-core support, Real-time scheduling, Provide GCC-based tool chain, Both Intel and PowerPC CPU support, Cryptographic security with access control, Memory management and scheduling	Available on request
Keil RTX	Deterministic RTOS with source code, Supports preemptive, collaborative and round-robin scheduling, Low interrupt latency with high-speed operations, Unlimited mailboxes, semaphores, mutex, and timers, Thread-safe and multithreading	Available on request
QNX Neutrino RTOS	Real-time availability, Comprehensive, layered security, Microkernel architecture, Adaptive partitioning, Available in safety-certified operating system editions, Designed to scale on the latest multicore SoCs	Starts at $0.37/hr
FreeRTOS	Stream & Message Buffers, Inter-task Communication, Source code organization, Heap memory management, Stack overflow protection, Supported microcontrollers	Available on request
MQX	Component-based architecture, Priority-based preemptive scheduling, Supports fast boot sequence, Simple and easy message passing, Integrated with 32-bit MCUs and MPUs, Offers customization by feature, size, and speed	Available on request
PikeOS	Separation kernel-based hypervisor, Real-time virtualization, Multiple and strictly separated partitions, Guest operating systems and applications, Compliant to the highest Safety & Security standards	Available on request

How Do We Evaluate and Select the Best Real-time Operating Systems for You?

When selecting the most suitable real-time operating system, we did a thorough evaluation based on several key factors. First and foremost, we carefully examined the features offered by each RTOS. These features include determinism, real-time scheduling, memory management, synchronization and user interface. 

Furthermore, we considered the performance metrics of each RTOS along with resource usage, speed, and responsiveness. We prioritize real-time operating systems that offer efficient resource utilization and responsive performance across a range of hardware configurations. 

Next, we thoroughly assessed the security features provided by each OS. This includes built-in security mechanisms such as encryption, access controls, and regular security updates. 

Lastly, we considered the community and support ecosystem surrounding each RTOS. Active community forums, official documentation, and professional support options are essential factors in ensuring timely assistance and troubleshooting resources. 

Regular Operating System vs. Real-Time Operating System 

Real-time operating systems (RTOS) are a crucial component of modern computing, distinct from regular operating systems in their focus, predictability, and task handling capabilities. Traditional OS (or regular OS) typically uses non-real-time scheduling algorithms which offers variable task execution times, whereas RTOS utilizes real-time scheduling algorithms to guarantee precise and predictable task completion within defined time constraints. Here’s a detailed comparison between regular OS and RTOS across various aspects: 

Regular Operating System vs. Real-Time Operating System
Features	Regular OS	RTOS
Primary focus	Maintain user responsiveness, multitasking, device management etc.	Used to handle tasks with strict timing constraints
Timely response	Not guaranteed	Guaranteed
Speed and Efficiency	Focuses on user experience and features, may have some overhead processes running in the background.	Focuses on speed and minimal overhead for critical tasks.
Latency	Average latency	Maximum latency
Resource Utilization	Variable depending on workload	Highly optimized
Examples	Windows, Android, macOS, etc.	Azure RTOS, FreeRTOS, QNX Neutrino, etc.
QNX Neutrino RTOS	Real-time availability, Comprehensive, layered security, Microkernel architecture, Adaptive partitioning, Available in safety-certified operating system editions, Designed to scale on the latest multicore SoCs	Starts at $0.37/hr
FreeRTOS	Stream & Message Buffers, Inter-task Communication, Source code organization, Heap memory management, Stack overflow protection, Supported microcontrollers	Available on request
MQX	Component-based architecture, Priority-based preemptive scheduling, Supports fast boot sequence, Simple and easy message passing, Integrated with 32-bit MCUs and MPUs, Offers customization by feature, size, and speed	Available on request
PikeOS	Separation kernel-based hypervisor, Real-time virtualization, Multiple and strictly separated partitions, Guest operating systems and applications, Compliant to the highest Safety & Security standards	Available on request

What is the Cost of a Real-Time Operating System? 

The cost of a real-time operating system (RTOS) can vary depending on several factors such as licensing model, features, deployment size, training, and more. Moreover, the pricing can also change depending on the specific requirements of a project. However, the price for RTOS typically ranges from $1000 to $10,000.