This week we are out in Cape Cod with Frannie's family, hanging out at the beach in Truro (where, incidentally, there was a shark attack a few weeks ago).  This week, we're renting a different house than normal -- it's an old run-down house next door to the cottages where Fran's family has vacationed forever, that was fixed up into rentable shape over the winter. Last night, as everyone was sleeping, a loud alarm went off.  A few minutes later, it went off again. It woke us up and we started investigating.  It turns out it was the smoke / carbon monoxide detector. We were a bit freaked out, because of carbon monoxide's reputation as the "silent killer" -- we didn't smell any smoke and couldn't detect anything out of the ordinary, but we also couldn't explain why the alarm was going off. Most importantly and disturbingly, neither of us knew what to do when the carbon monoxide detector went off.  Do we call the fire department?  Press reset?  Call the person we're renting the house from (who is 200 miles away and sleeping?) How do we know this isn't just a bad battery?  Ultimately, I pressed the "test / reset" button (that's what you're supposed to do, right?) and the intermittent alarm stopped, but we weren't even sure how to tell what that meant. We didn't know any of the answers.  So, in the midst of a mild panic about the kids asphyxiating in their bedrooms, we turned to Google.  We searched to try and figure out what exactly you're supposed to do when that alarm actually does go off.  Turns out a lot of people have the same question.  I looked all over, and even ended up in a PDF of the product manual for a detector -- amazingly, the whole manual has only one short paragraph on what to do when the alarm goes off. Eventually, we came across some information (somewhere; I can't remember) saying that in cases of power surges or interruption, the alarms can go off -- and I remembered that the lights in the living room had been flickering the night before.  And to, in these cases, press reset to stop the beeping and wait to see if the alarm resumes.  If not, then don't worry.  Ultimately, this answer worked for us, and we were able to get over the scare and try and get back to sleep. But the whole experience was kind of dumbfounding.  The fact that we really had no idea what to do in case of alarm -- how to tell a real emergency from a false alarm (especially when I've changed the batteries in 5 smoke detectors in my in-laws' house in the past few months to stop the beeping).  How to interpret the beeps; who to call; what to do.  What good is an alarm if you're not sure what to do when it goes off?  It made me really appreciate all those fire drills we did as kids in school. All in all, it reminds me of the (old?) saying in computer land -- having backup procedures is good, but what you really need are restore procedures.  A backup is no good if you aren't sure you can use it or don't know how.