Threading Question

[Brent Fulgham <brent.fulgham@xpsystems.com>]

I've been reading through the MzScheme C API, and had a few
questions:

1.  Does an API function exist to create a new instance of the 
MzScheme interpreter?  Or should unrelated Scheme sessions just
take place using individual threads?

2.  If the answer to #1 is "use threads", how much isolation
is there between one thread and another.  For example, if I
define a function in a particular thread, do other threads see
this function definition?  Does it matter when the thread is
"forked" from the main thread?

3.  Does MzScheme support full "free" threading in which separate
threads can execute on separate processors (if they exist)?

Thanks,

-Brent