Today's Mac Gem is a simple one, but it's sure to be useful to developers, frequent users of Boot Camp, and anyone else who regularly boots their Mac from different startup volumes. A few years back, I covered BootChamp, a utility that lets you restart an Intel Mac into Boot Camp without having to open System Preferences and permanently change your startup disk, or without having to restart and hold down the Option key, waiting for OS X's Startup Manager to appear.