Writing directly to screen memory on XENIX/UNIX

[martin]

I know this question has been asked before to these newsgroups, but
I was unable to find anything in my archives pertaining to the
subject.  My question is:

Has anyone ever written directly to the screen memory with UNIX or
XENIX on a PC?  I know that I probably open /dev/mem and start 
writing at the ega address space (after probably massaging the
video controller or whatever).  The UNIX that I am running is
V.3.1 for the 386.  

Please send mail to me directly.  I do not want to get flamed all over
the place by people not wanting to hear about this.. 

thanks
Martin Wilde