 as pointers.
Unless the client program has made heap object layout information
available to the collector, any heap objects found to be reachable from
variables are again scanned similarly.

<LI>
<I>Sweep phase</i> Scans the heap for inaccessible, and hence unmarked,
objects, and returns them to an appropriate free list for reuse.  This is
not really a separate phase; even in non incremental mode this is operation
is usually performed on demand during an allocation that discovers an empty
free list.  Thus 