I've been reading about DRb from several sources including the
documentation at the beginning of drb.rb. I'm troubled by the
mechanism for passing objects by reference instead of by value. From
what I've read you have to add "include DRb::DRbUndumped" to the class
of the objects being passed. What if I want to pass some objects of
that type by reference and others by value?

-- 
R. Mark Volkmann
Partner, Object Computing, Inc.