Lisp machine
The original Lisp machine operating system was developed in Lisp Machine Lisp, using the "Flavors" object-oriented extension to that Lisp. Symbolics provided a successor to Flavors named "New Flavors". Later Symbolics also supported Common Lisp and the Common Lisp Object System (CLOS). Then Symbolics Common Lisp became the default Lisp dialect for writing software with Genera. The software of the operating system was written mostly in Lisp Machine Lisp (named ZetaLisp) and Symbolics Common Lisp. These Lisp dialects are both provided by Genera. Also parts of the software was using either Flavors, New Flavors, and Common Lisp Object System. Some of the older parts of the Genera operating system have been rewritten in Symbolics Common Lisp and the Common Lisp Object system. Many parts of the operating systems remained written in ZetaLisp and Flavors (or New Flavors).