I'm wondering what constitutes "inactive" in "Put the computer to sleep when it is inactive for 15 min." in the System Preferences. On the Internet, I read somebody reporting that her/his Mac went to sleep while burning DVD; another person says that DVD burning keeps her/his Mac from sleeping. What about running applications? I can imagine that inactivity can be defined as a low CPU load and the lack of keyboard and mouse input. (Where can one find such a definition?)
My specific problem is that MacPort is taking a long, long time to compile and install an application, and I'm very sleepy now :-) I hope my Mac will go to sleep after MacPort finishes its job.