Paul, go with the v2.4 linux kernel series and rtai, it is ready(=stable) for general use. Regards Max -- Max Heise <max.heise-at-gmx.net> Student Mechatronik/Automatisierungstechnik FHT Esslingen PGP public key from: http://www.fht-esslingen.de/~mahemt01/pgp50i.pub or any keyserver