-be satisfied with having after it is done. Initially it is 8192 words.
-If the total amount of reclaimed storage is less than *min*, the
-garbage collector will ask the operating system for enough storage (in
-1024 word blocks) to make it up. N.B.: the system may be incivil
-enough not to grant the request; in that case, the garbage collector
-will be content with what it has, **unless** that is not enough to
-satisfy a **pending** request for storage. Then it will inform you
-that it is losing. A large *min* will result in fewer total garbage
-collections, but they will take longer since the total quantity of
-storage to be dealt with will generally be larger. Smaller *min*s
-result in shorter, more frequent garbage collections.
+be satisfied with having after it is done each time. Initially it is
+8192 words. If the total amount of reclaimed storage is less than
+*min*, the garbage collector will ask the operating system for enough
+storage (in 1024-word blocks) to make it up. N.B.: the system may be
+incivil enough not to grant the request; in that case, the garbage
+collector will be content with what it has, **unless** that is not
+enough to satisfy a **pending** request for storage. Then it will
+inform you that it is losing. A large *min* will result in fewer total
+garbage collections, but they will take longer since the total
+quantity of storage to be dealt with will generally be larger. Smaller
+*min*s result in shorter, more frequent garbage collections.
+
+*exh?* tells whether or not this garbage collection should be
+"exhaustive". It is optional, a `FALSE` by default. The difference
+between normal and exhaustive "copying" garbage collections is whether
+certain kinds of storage that require complicated treatment (for
+example, associations) are reclaimed. An exhaustive garbage collection
+occurs every eighth time that the "copying" algorithm is used, or when
+`GC` is called with this argument true, or when a normal garbage
+collection cannot satisfy the storage request.
+
+*ms-freq* gives the number of times the "mark-sweep" algorithm should
+be used hereafter for every time the normal "copying" algorithm is
+used. Giving `0` for *ms-freq* means never to use the "mark-sweep"
+algorithm, and giving `<CHTYPE <MIN> FIX>` means (effectively) always
+to use it. The "mark-sweep" algorithm uses considerably less processor
+time than the "copying" algorithm, but it never shrinks the
+free-storage pool, and in fact the pool can become fragmented. The
+"mark-sweep" algorithm could be useful in a program system (such as
+the compiler) where the size of the pool rarely changes, but objects
+are created and thrown away continuously.