How do you compare real-time and embedded operating systems?

1 What are real-time operating systems?

A real-time operating system (RTOS) is an operating system that guarantees that certain tasks are completed within a predefined time limit, regardless of the load or complexity of the system. This means that an RTOS must be able to prioritize and schedule tasks according to their urgency and deadlines, and handle interrupts and exceptions without causing delays or errors. An RTOS is essential for applications that involve critical or time-sensitive operations, such as medical devices, air traffic control, or nuclear reactors.

2 What are embedded operating systems?

An embedded operating system (EOS) is an operating system that is designed to run on a specific hardware platform, usually with limited resources and functionality. An EOS is typically optimized for a single purpose or function, and has a small footprint and low power consumption. An EOS is often integrated with the hardware device, and may not have a user interface or support for external devices or networks. An EOS is suitable for applications that require low cost, high performance, and minimal maintenance, such as smart watches, cameras, or sensors.

3 How do they differ in requirements?

One of the main differences between real-time and embedded operating systems is their requirements. An RTOS must meet strict timing constraints and ensure that tasks are executed within their deadlines, while an EOS must fit into a constrained hardware environment and optimize for resource usage and efficiency. Therefore, an RTOS must have a fast and predictable kernel, a flexible and scalable scheduler, and a robust and responsive interrupt handler, while an EOS must have a small and simple kernel, a minimal and modular design, and a low and stable power consumption.

4 How do they differ in features?

Another difference between real-time and embedded operating systems is their features. An RTOS must provide features that support real-time functionality and performance, such as preemptive multitasking, priority-based scheduling, inter-task communication and synchronization, and real-time clock and timers. An EOS must provide features that support embedded functionality and performance, such as device drivers, memory management, file systems, and network protocols. However, some features may overlap or vary depending on the specific application and platform of the operating system.

5 What are some examples of real-time operating systems?

Real-time operating systems (RTOSs) are used in a variety of applications, each with its own advantages and disadvantages. Popular RTOSs include FreeRTOS, a free and open-source RTOS that supports multiple architectures and platforms; VxWorks, a commercial and proprietary RTOS used in high-end and mission-critical applications; QNX, a commercial and proprietary RTOS based on a microkernel architecture; and RTLinux, a variant of Linux combining a real-time kernel with a standard Linux kernel. Each of these RTOSs offer different features and capabilities, from rich libraries to high security and reliability.

6 What are some examples of embedded operating systems?

There are many examples of embedded operating systems, each with its own strengths and weaknesses. Linux is a free and open-source EOS based on a monolithic kernel, providing a large set of features, applications, and customization options. Windows Embedded is a family of commercial and proprietary EOSs based on Windows, offering a user-friendly interface and comprehensive development environment. Android is a free and open-source EOS based on the Linux kernel, popular for mobile devices and offering an extensive ecosystem of apps and services. Finally, iOS is a commercial and proprietary EOS based on the Darwin kernel, providing a secure platform for iPhones and iPads with an exclusive app and service ecosystem.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?