TinyOS is an ultra-lightweight real-time OS designed for IoT and embedded devices with limited resources. According to the developer, the kernel footprint is less than 10KB, and the minimum RAM required for operation is 2KB. It supports preemptive priority-based scheduling.
TinyOS, a Lightweight RTOS for Cortex-M, Released with Kernel Under 10KB
This article is a translation. Read the Japanese original
Supported architectures include ARM Cortex-M0/M3/M4/M7, RISC-V RV32I, and AVR ATmega. An ARM cross-compiler is required for building, and operation can be verified in an emulation environment using QEMU. Specifically, it has been verified that SysTick timing and context switching via PendSV complete successfully on the mps2-an385 target (Cortex-M3).
The API includes task management, synchronization primitives such as mutexes and semaphores, event groups, queues, and timers. The specification automatically enables TLS support if mbedTLS is present in the environment. Additionally, several demo samples are included, such as LED blinking and MQTT publish/subscribe.
Source: Show HN: TinyOS – A minimalist RTOS for Cortex-M written in C (HN 102pt, 43 comments) (HN Search (backfill), 2026-04-04)