>What exactly is subsumption

   Roughly (that is all I know), subsumption is a fixed priority scheme that
 determines which modules message gets where.  For instance, if several modules
 send a message to a motor, the message from a higher priority module can
 subsume (or replace) the message from a lower priority module.  In practice,
 there are many more implementation characteristics.  This method was pioneered
 by Rodney Brooks, who heads the robotics lab at MIT.  The best description is
 in the book, 'Minimalist Mobile Robotics', by Jonathan Connell (Academic Press,
 1990).

>and how do you usually implent it in a PIC?

   Don't know.  The original system used several processors linked by comm lines
 and some additional external logic to handle the subsumption.  The above book
 describes the workings.

>I have vague ideas but I am not quite sure.  I would also like to know of
>any robotics mailing lists and newsgroups.

  Try the robotics FAQ by ftp from rtfm.mit.edu in directory
 pub/usenet-by-group/comp.answers/robotics-faq.

  There's a new publication called The Robotics Digest coming out in January;
 mail to 102505.3055@compuserve.com (the publisher) to inquire.

  I'm also beginning a PIC based robot, e-mail me privately.

John-