Is Linux only for the poor? (ZDNet)

Asterisk could be run with real-time scheduling priority. Thus a 100% CPU loop in it (e.g.: an endless loop in the dialplan) would make Asterisk the only process getting CPU time. And thus the computer is quite unresponsive.

This, however, changed in 2.6.25: after a short while, such a loop will only get 95% CPU and thus leave you with a somewhat functional system (functional enough to troubleshoot. Or at least to shoot down the offender)