Lightweight RTAI for IA-32

Michael Heimpold and Robert Baumgartl

Using the IA-32 architecture for time-critical tasks allows highest computing performance at reasonable hardware cost. Because many open source real-time operating systems are based on Linux, the comparatively high resource requirements of Linux also apply to these systems. In this work we present a port of the RTAI API to a bare IA32 machine which eliminates Linux' core subsystems. Instead of a full API reimplementation we used an established Linux/RTAI as a starting point and gradually eliminated the Linux functions. This methodology minimizes changes to the RTAI codebase and ensures easy maintenance of the resulting code base. Our measurements show that the resulting system is as efficient as a conventional RTAI. The uncompressed memory footprint of the kernel is about 370 KiB. Hence, the resulting system is a small and efficient real-time kernel of clear design which provides the RTAI API and is ideally suited for embedded systems with low resources.