1. Linux User space Kernel space Low prio high prio Linux scheduler main thread rt_thread_create Runs in User Mode : can only address User space Linux syscall readfile(..), printf(..) Kernel module Kernel module Kernel module Linux Kernel Communicates with terminal to display text of printf filesystem module (ext3.ko) communicates with harddisk to read the file Kernel module

2. RTAI – modes, spaces and schedulers User spaceKernel space Low prio high prio not realtime hard realtime Linux scheduler Real-time scheduler RT task Kernel module init_module() rt_task_start Rtai Kernel function call Linux Kernel Shell : # insmod Runs in Kernel Mode : can address User and Kernel space

3. Levels and API’s User spaceKernel space Low prio high prio Linux scheduler Real-time scheduler rt_printk printk printf Linux Kernel Rtai Kernel thread

4. LXRT User spaceKernel space Low prio high prio Linux scheduler Real-time scheduler FIFO Sched other mainthread rt_thread_create thread rt_make_soft_real_time rt_make_hard_real_time Runs in User Mode : can only address User space Rtai Kernel LXRT syscall Linux Kernel Linux syscall hard realtime soft realtime