Last night the whole family got into a multiplayer Minecraft game for the first time in a while. Weirdly enough, *one* system was showing way to many materials as copper. Even stuff like snow. WTF?

Well, we realized it was after 7 PM local time, which meant on UTC time it was already April 1, so it must be this year’s April Fool’s joke for Minecraft. (Or in this case, one of the mods.) But why only on one computer?

Then it hit me: The host was a Windows machine, which means the hardware clock is set to local time (instead of being set to UTC and just displaying local time). I was connecting from a Linux box that dual-boots, so I’d long since set the hardware clock to local time so Windows wouldn’t fight with it. The one showing all copper, all the time, was a Mac, which doesn’t dual boot, and uses Unix under the hood, so its hardware was set to UTC, and it was the only computer of the three that was already running in April 1.