Realtime Linux Projects

There are a number of projects underway to augment the linux operating system with a Realtime subsystem. All of the projects below claim to have some support for the ARM:

Balloon 2

Cambridge University Department of Engineering looked at the possibility of using RTAI on a Balloon 2 board back in October 2005. Eventually, of the six tests in the RTAI test suite, two worked. Of the four that did not work, all three of the 'user space' tests failed with 'illegal instruction' errors - probably due to the RTAI/Adeos syscall interface not working, and the final test involved using floating point code in the kernel.

The work was done using RTAI version 3.2. This version appeared at about the when the RTAI code base was modified to use the Adeos nanokernel instead of the 'RTHAL' for interrupt interception, RTAI was about to split with Xenomai, and RTAI was dropping support for the StrongARM.

The work involved solving two separate problems.

  1. Applying the Adeos kernel patch the the Balloon's customised Linux kernel
  2. Putting StrongARM support back into RTAI 3.2

Since the work was done the Linux Kernel has been through several updates, the Adeos nanokernel has been updated (and there is now a cut-down version: ipipe aimed at providing just enough support for a RTOS and nothing more) and Xenomai is now a separate project again. The patches to the kernel and to RTAI are available below in case anybody finds them useful.

Patches:

Adeos kernel patch: linux-2.6.8.1-tcl1-adeos.patch

RTAI patch - Todo

Balloon 3

Watch this space...

Balloonboard: BalloonRealtime (last edited 2009-02-22 21:00:16 by localhost)