This directory contains various third-party opensourced system-building tools. The code here is current as of February 1, 2005; you may want to check the originating project's homepages to see if more recent versions are available. "defsystem.lisp" is part of the clocc project on SourcForge: . It's a "system definition facility" which provides functionality similar to that offered by the Unix "make" program. It was originally written by Mark Kantrowitz and has been maintained and enhanced by many people; I believe that Marco Antoniotti is currently the principal developer. This is version 3.4i of DEFSYSTEM (which is often called "MK-DEFSYSTEM"). Note that, for historical reasons, DEFSYSTEM will try to redefine the CL:REQUIRE function. "asdf.lisp" is Another System Definition Facility and is available as part of the cclan project on SourceForge: . It was written by and is maintained by Daniel Barlow. "asdf-install" is a library which can be used to download CL packages from the Internet and which uses ASDF to build and install them. It's also part of the cclan project and was originally written (for SBCL) by Dan Barlow. It's since been ported to several other CL implementations; Marco Baringer did the OpenMCL port. There's excellent documentation on asdf-install in the asdf-install/doc directory. As that document mentions, asdf-install is designed to use the GnuPG package to validate cryptographic signatures associated with asdf-install-able packages, though it can apparently be configured to work in an environment in which GnuPG is not available. Downloading code from publicly-writable Internet sites - without the ability to verify that that code's really what it claims to be and from the author who claims to have provided it - is obviously a dangerous and unwise thing to do. It's strongly recommended that people ensure that GnuPG is installed (and ensure that asdf-install is configured to use it) before using asdf-install to download packages. (GnuPG packages for OSX are available from . Most Linux distributions offer GnuPG through their packaging system; further information on GnuPG is available at .