low-level message passing

[Jonathan Shapiro]

   I also don't understand the "page-fault-on-return problem", unless you
   mean it is another opportunity (of many) for users (including pagers) to
   get into deadlock.

I believe that Bryan is using "page fault on return" to refer to the
case in which a client calls a server expecting a return, and on
return the client's receive buffer is found to have an invalid page
(i.e. one for which there is no mapping).  This really isn't a page
fault issue.

Jonathan