HI Snarf,
Some 8 or 10 years ago we used to run a real time OS named Lynx. Since then we have only used Linux. Today we run a patched real time Linux, see
www.osadl.org.
www.osadl.org
The Linux vanilla kernel itself has today really good support for real time capabilitites.
On the osadl-website there are good instructions on how to download and confgiure this kernel.
A failover system is not planned for addition in the near future.
Plans for implementing support for EterCAT or Ethernet Powerlink exist but I have no good answer on when that will be. Any contributions on this matter will of course be appreciated. I looked a little bit at an open source solution for EtherCAT but I found it very hard to find good documentation (any hints would be appreciated, both for Powerlink and EtherCat).
/Robert