Some notes on using "5/1/90 May Day PCL (REV 4b)" with KCL and AKCL. 1. KCL will try to load the PCL file "init" when it starts up, if you rename the files as is mentioned in defsys.lisp and the currect directory is the one containing PCL. I suggest that you do not rename any file except maybe "defsys", and also that you change the (files-renamed-p t) to (files-renamed-p nil) in defsys.lisp. 2. Do not comment out the file kcl-patches.lisp, even if you are using AKCL. It contins a patch to make compiler messages more informative for AKCL, and also sets compiler::*compile-ordinaries* to T, so that methods will get compiled. 3. While fixup.lisp compiles, there will be a pause, because KCL's compiler is not reentrant, and some uncompiled code is run. If you want, you can change the form (fix-early-generic-functions) to (fix-early-generic-functions t) in fixup.lisp to see what is happening. 4. (If you are using AKCL 605 or newer, skip this step.) If you want, you can apply the changes in kcl-mods.text to your KCL or AKCL to make PCL run faster. The file kcl-mods.text is different from what it was in versions of PCL earlier than May Day PCL. If you do not make these changes, or if you made the old changes, things will still work. 5. If you are using AKCL, and you previously used the kcl-low.lisp file from rascal.ics.utexas.edu, you should not use it this time. The kcl-low.lisp that comes with May Day PCL works fine. (If you insist on using an old version of kcl-low.lisp, you will need to use an old version of the KCL part of fin.lisp as well: this is what is done for IBCL, by the way.) 6. I recommend that you use AKCL version 457 or newer rather than using KCL or an older version of AKCL, because there are some bugs in KCL that cause problems for May Day PCL.