I have tried several versions of SHRDLU, binary and source, but so far I haven't found one that works. Some people claim it never really worked well. Winograd himself seems to think it did, and there is what seems to be a working demo in a 1973 TV documentary. Others say it needed heavy manual patching to be somewhat usable, and those patches didn't make it to the source code files.
Yes, I've seen the sources that say it never was stable, but I assume that at least what's in the recorded demo was at some point possible to run; of course it might be coming from a long-lost source/or binary.
