Every so often, say once an hour or so, my Celeron 400 server runnng Debian unstable emits three short beeps. They sound quite similar to the error beeps that occur on system start-ups, although this system boots and seems to operate just fine. I'm not sure if this is a feature of software I'm running, peculiar to this particular hardware or what. If anyone has any ideas what it might be, I'd certainly appreciate your satisfying my curiosity.