Does anybody have any pet peeves and gripes about using systems with a compartmentalised security model- things that took ages to do even though they didn't really impact security, features that just got in the way or were too complicated to really use, etc? I'm currently working on a problem that seems to have some analogies to the compartmentalised problem, running code with various levels of trust were deliberate read-up and accidental write-down could be a breach. I've personally never used a system of this sort, but I've heard from friends in the RAF doing COM/SEC (more COM than SEC) that MLS can be a real pain at times. [for the truly paranoid, the RAF operates a network of communication satellites called Skynet :-)] Simon p.s. still no luck on the Hackers soundtrack - I did recognise a few prodigy tracks though (defun modexpt (x y n) "computes (x^y) mod n" (cond ((= y 0) 1) ((= y 1) (mod x n)) ((evenp y) (mod (expt (modexpt x (/ y 2) n) 2) n)) (t (mod (* x (modexpt x (1- y) n)) n))))