Apple’s Mavericks operating system set the OS X early-adoption record last month, with a third of all Macs running the new edition within just weeks of its introduction. The fast uptake validated Apple’s rationale for giving away OS X 10.9, aka Mavericks. “What’s most important to us is seeing the software in the hands of as many Mac users as possible,” Craig Federighi, who leads software engineering at Apple, said during an October event where he announced that Mavericks would be free. “Today, spending hundreds of dollars to get the most out of your computer are gone,” Federighi added, taking a shot at rival Microsoft, which charges $199 for its Windows 8 Pro upgrade. Mac users running 2012′s Mountain Lion, 2011′s Lion and 2009′s Snow Leopard on compatible systems have been able to download Mavericks from the Mac App Store free of charge since Oct. 22.