nice question (pun optional)

[steve%prd.co.uk@localhost (Steve Blinkhorn)]

I have a process that I want to run at the highest possible priority.
Tt curr4ently runs with NICE set at 0 and PRI showing at 43.  Most
other swtuff shows up with a PRI at 85.  As I understand things, the
highest priority is 0.

So I use renice(1) to set NICE to -20, which is the highest priority,
but the value of PRI goes from 43 to 63, i.e. a lower priority.

This happens regardless of which shell I use, BTW.

What's going on, or what am I misunderstanding?

--
Steve Blinkhorn <steve%prd.co.uk@localhost>