ASDF was originally not written by Fare Rideau. It was developed by Dan Barlow in 2001/2002. He did not use MK-DEFSYSTEM, because he wanted a free/open-source D

ASDF was originally not written by Fare Rideau. It was developed by Dan Barlow in 2001/2002. He did not use MK-DEFSYSTEM, because he wanted a free/open-source DEFSYSTEM with an implementation using more of CLOS and easier to maintain. ASDF was later developed into ASDF2 and 3 with a lot of work by Fare Rideau and others.