DuinOS

FreeRTOS is an open source, real-time operating system for microcontrollers that makes small, low-power edge devices easy to program, deploy, secure, connect, and manage. Distributed freely under the MIT open source license, FreeRTOS includes a kernel and a growing set of software libraries suitable for use across industry sectors and applications. This includes securely connecting your small, low-power devices to AWS Cloud services like AWS IoT Core or to more powerful edge devices running AWS IoT Greengrass. FreeRTOS is built with an emphasis on reliability and ease of use, and offers the predictability of long term support releases. A microcontroller contains a simple, resource-constrained processor that can be found in many devices, including appliances, sensors, fitness trackers, industrial automation, and automobiles.

The Keil RTX is a royalty-free, deterministic real-time operating system designed for ARM and Cortex-M devices. It allows you to create programs that simultaneously perform multiple functions and helps to create applications which are better structured and more easily maintained. Royalty-free, deterministic RTOS with source code. While it is certainly possible to create real-time programs without an RTOS (by executing one or more functions in a Super-loop), there are numerous scheduling, maintenance, and timing issues that an RTOS like the Keil RTX solves for you. For a more detailed comparison between RTOS and Super-loop, take a look at the advantages of using an RTOS. High-Speed real-time operation with low interrupt latency. Small footprint for resource constrained systems. Unlimited number of tasks each with 254 priority levels. Unlimited number of mailboxes, semaphores, mutex, and timers. Support for multithreading and thread-safe operation.