Lisp machine
Zmacs is one of the many variants of the Emacs text editor. Zmacs was written for the MIT Lisp machine and runs on its descendants (Symbolics Genera, LMI Lambda, TI Explorer). Zmacs is written in Lisp Machine Lisp (called ZetaLisp on Symbolics Lisp Machines). It is based on the ZWEI programming substrate, which stands for "Zwei Was EINE Initially"; Zwei was a collection of routines which could be used to easily implement other programs, like the Symbolics mail program, "Zmail".