Threads

Good evening all. I am trying to learn how OpenGL operates via cl-opengl 
and
cmucl-19e. While I can compile the graphics demos and run them, I lose 
control of cmcl's
repl. I can certainly type characters into it; there is no eval running 
as far as I can see.
Those characters appear to be fed to eval when I kill the graphics 
loop/processes.

Members of the cl-opengl list tell me I need a compiler which can 
produce threaded
code, (at least) one for opengl and, presumably, one for cmucl's repl. 
So far I have been
unable to find out how to persuade cmucl to help me here.

Perhaps someone of you can point me to documentation about ensuring the 
necessary
division of processes so that I can plough on into opengl.

Thx for any and all advice and assistance.

Cheers /Greg Bennett