My Dad worked on those as I was growing up, up at the National Center for Atmospheric Research in Boulder Colorado, where part of Sleeper by Woody Alen was filmed. You’d sign up for some window of time on them. I never saw a cray-1 except the one they had open to visitors – not running. I think the first one I remember is the cray-xmp or mp or something. I rendered a picture using povray on one when I was in highschool I think – don’t think I was supposed to…don’t tell anyone.