[wduquette]

I used DEC's VAX OPS5 for a couple years about around 1990. I quite liked it, and the later versions had some really nice extensions over Forgy's original design.

Then we discovered that our particular rule base could easily be ported into C using a sequence of nested if/thens that ran much faster, and we stopped using OPS5. It was a great tool for doing the initial development, though.