Close encounters of the CADR kind

That might actually be the CONS Machine (effectively a prototype CADR); Greenblatt looks awfully young in that picture! Also, I don't recall him being super-involved in the CADR work. (You might ask him which it is!) The CONS CPU backplane is apparently now at the CHM: http://www.computerhistory.org/collections/catalog/102647223 My memory of the CONS machine is that, like the Chess Machine, it was a special purpose CPU hung off the AI PDP-10. (Or maybe the Chess Machine was attached to MC? I forget.) However, while that may have been its state early on, in reviewing some CONS documents I discovered that it was eventually given a keyboard and display, although it did remain hooked up to the PDP-10. The CONS machine is described in 3 AI Lab publications: Working Paper #79, Working Paper #80 ("CONS", by Tom Knight), and Memo #444 ("LISP Machine Progress Report"), The first is available here: http://www.textfiles.com/bitsavers/pdf/mit/cadr/Greenblatt-The_LISP_Machine… but it's just an architecture document. Memo #444 has an extensive "Current Status - August 1977" section, which gives more info about the CONS machine as built. Noel