TinyOS emerges as a new ultra-lightweight real-time operating system (RTOS) specifically designed for Cortex-M microcontrollers, targeting resource-constrained IoT and embedded applications. Developed in C, it boasts a kernel footprint under 10 KB and requires only 2 KB of RAM, making it exceptionally suitable for devices with severe memory limitations. Key features include preemptive priority-based scheduling with 256 priority levels, round-robin scheduling within the same priority, and O(1) priority lookup via a bitmap. Support spans Cortex-M0/M0+/M3/M4/M7 architectures, including popular hardware like STM32, nRF52, Raspberry Pi Pico, and RISC-V ESP32-C3, with experimental AVR support.

This focus on minimal resource usage and broad hardware compatibility positions TinyOS as a compelling choice for developers building compact, efficient IoT solutions.