LISP-AND-MACSYMA Help DOCUMENTATION
Symbolic computation tends to create a good deal of garbage, and effective handling of this can be crucial to successful completion of some programs.
Under GCL, on UNIX systems where the mprotect system call is available (including SUN OS 4.0 and some variants of BSD) a stratified garbage collection is available. This limits the collection to pages which have been recently written to. See the GCL documentation under ALLOCATE and GBC. At the lisp level doing (setq si::*notify-gbc* t) will help you determine which areas might need more space.LISP-AND-MACSYMA Help DOCUMENTATION