>>I am not an MVS person.  If MVS people want to tie-in, I would think
>>a good MVS system programmer might take the challenge.
 
>                                            [...]   Any system which
>depends on having VM code on your host will automatically cut off a
>large portion of the net from participating.  /June
 
You don't need a server on each machine as long as the nearest neighbor
doesn't mind extending service to you.  After all, you get LISTSERV
service on MVS by using someone else's server.
 
The real issue is that of interactive messages -- can you send and also
receive them.  For VM, the 'TELL' command does the trick; for VMS, 'SEND'
will do it; UREP has *something* also.  MVS systems typically do not, but
there are exceptions (ISU can do it).  It would depend on the underlying
flavor of JES, plus whatever terminal service you have (TSO, Wylbur, etc).