>   I don't know if there's any other way to set a negatice nice other than
> running it as root or setting the effective UID of the program to root
> (and the program changes its own nice to the desired value). The latter one
> is very dangerous if there are other users in the same system.
>   Perhaps theres another way (there's so much I don't know about unix...).

According to the man page for "nice", only the superuser can request
a negative "nice" value (i.e. higher priority). Any user can request
a positive value (i.e. lower priority).

You might build a script that invokes the renderer with appropriate
arguments and make that script setuid root. As pointed out above,
though, this would be dangerous if there are other users on the box.
Is this a single-user computer?

Setting the nice value might not be necessary, though. If you're the
only user and nothing else is going on in the background, it just
might be that POV will get the lion's share of cycles anyway. Try
running "top" to see what is running on the box. Anything that's
in a sleeping state won't be taking cycles, as they're waiting on 
an external event before being scheduled to run again, so no CPU
time is going to those processes anyway. I just opened up a shell
on my machine at home with X and Netscape running (plus loads of
support stuff), and everything except "top" was sleeping, waiting
for input.

If you're not running anything computationally intensive (number-
crunching, downloading a file, whatever) at the same time you're
running POV, I doubt you'll see any significant speedup from the
negative "nice" setting.

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