Warner Losh wrote: The original Macsyma was developed at MIT. I think the LCG group at Project MAC? It was written in Maclisp. It was ported over to Maclisp offspring such as Lisp machine Lisp, NIL, and Franz Lisp. They all used a common base at first, with conditionals for different flavours. In 1982 MIT licensed Macsyma to Symbolics, but also made it available to the US Department of Energy. Apparently DOE used the NIL. Maxima is based on DOE Macsyma and was subsequently GPLed. What Eric et al managed to get running is a mix of files from ITS dumps, and an old Lisp machine version. The Lisp machine version still has the conditionals intact. Source files are taken from ITS where possible, else from the Lisp machine. Where no source file was found anywhere, binary files from ITS were used to fill gaps.