Thank you very much Rob.

It's not easy to understand Rio to me, because this is my first 
experience to see her functions and implementation.  Please
forgive me if I'm too noisy on this topic.

When I do "ps", I find 7 rio processes for one window.  I now
think I got it right(???).  Those are, in the order from early to late,
1) main process, 
2) mouseproc made from initmouse(), 
3) kbdproc from initkeyboard(), 
4) timeproc from timeinit(), 
5) wctlproc from filsysinit() in fsys.c, 
6) filsysproc also from the same function as (5), 
7) /bin/rc or approapriate file to be called
        called from initcmd() or new().

Then, No. (2) and (5) procs are marked as rendez.  I looked into
sources, however, I failed to understand where the No.2 and 5
processes are called rendezvous.  I know I'm missing something...

Kenji