They still do both, here's their hardware offering which is hardware and softwar...

They still do both, here's their hardware offering which is hardware and software based: http://www.stratus.com/solutions/platforms/ftserver/

And this is there software based solution which runs on commodity hardware: http://www.stratus.com/solutions/software/everrun-enterprise...

I only work with the latter but have heard the hardware offering is bulletproof.