Some lisp implementation can be run on different architectures.
If users keep the same home on different computers this will lead to collision in ~/.slime/fasl/* directories.
To generate the directory name for fasl files, I use the following function, adding the machine type:
(defun first-word (text) (let ((pos (position (character " ") text))) (if pos (subseq text 0 pos) text)))
(defun implementation-id () (format nil "~A-~A-~A" (first-word (lisp-implementation-type)) (first-word (lisp-implementation-version)) (first-word (machine-type))));;implementation-id