Re: PID sequences

Klaus Lichtenwalder (
Fri, 27 Feb 1998 09:42:02 +0000 (WET)

On Wed, 25 Feb 1998, George Kyriazis wrote:

> Sorry for the dumb question, but what's the advantage of random PIDs?
> Personally, I like sequential PIDs, since just by looking at the PID number
> I know (ballpark figure) how many processes have run between process A
> and B.. (ie. I know if I have to optimize my shell script or not).
> To me, sequential PIDs can be treated as random, but with an really bad,
> but cheap, generator algorithm.
> So, what's the issue, really?

Well, predictable PIDs (as sequential pids are) can be considered a
covert channel for smuggling information out of the box. That's at least
the explanation from IBM AIX for using random pids. Guess there's
something written in some POSIX document as well?

Klaus Lichtenwalder
Klaus Lichtenwalder, Dipl. Inform., PGP Key: email to fax: +49-89-91072699
Mausoberflaechen sind meistens pelzig -- Ricarda

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