Examples of RTOS

FreeRTOS

Many CPU architectures (8 to 32 bit).

Tick and tickless operation.

Task code is cyclic.

Scheduler is part of the kernel.

Allows preemption control.

IPC: queues, buffers.

Synchronization: semaphores, mutex, ...

Monolithic application (kernel application code in a single executable file).

Xenomai: Real-Time Framework for Linux

Allow the use of Linux for Real-Time applications.

Dynamically loadable modules.

Tasks may execute on kernel or user space.

POSIX (partially compat).

Cyclic tasks.

Support to several IPC mechanisms, both between RT and NRT tasks (pipe, queue, buffer, ...).

Several “skins”.

SHaRK: Soft and Hard Real Time Kernel

Research kernel, main objective is flexibility in terms of scheduling and shared resource management policies.

POSIX (partially compat).

For x86 (i386 with MMU or above) architectures.

Cyclic tasks.

Several IPC methods.

Concept of Task Model(HRT, SRT, NRT, per, aper) and Scheduling Module.

Policing, admission control.

Monolithic application.