I have some ring oscillator designs submitted to MPW6. I now have a sample as this was one of the designs used for validating the caravel fixes. I'm looking at how close the STA predicts the ring frequency compared to what I measure. The SDF file seems to be incorrect though, with delays of 0ps. I think this is because back at MPW6, the timing wasn't so good. Can I use openRCX to re-extract the SDF from the GDS? @Matt Liberty do you have any ideas?

rcx works on DEF not GDS as it is part of OR. That said you should be able to run it in OR

Matt, You can re run the timing closure on MPW6 with SDF using the later versions of OL (from MPW7 or later) and will get accurate results as much as is possible from SDF. For spice like sim you need a transitor and parasitic netlist extraction with RCX to run spice. That flow works through magic right now AFAIK and should work if the design is small. Mitch Bailey or TIm is teh fastest path to getting a netlist into a spice type simulator.