Like 2009, this year is one of dueling operating system upgrades, when the two biggest OS rivals face off with new editions.
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Now it's the turn of the numbers to tell their story.
0 -- The price of an upgrade to OS X Mountain Lion for buyers of new Macs who purchased their Lion-powered systems starting June 11. The program, called "Up-To-Date" by Apple, continues as long as either Apple or its authorized resellers sell Lion-equipped Macs. The free upgrade will be available from the Mac App Store after buyers fill out a form to be posted on this page of the Apple website.
It's also what a Windows user will pay for the Windows Media Center add-on after upgrading to Windows 8 Pro. The add-on, which will come with a price of some sort after Jan. 31, 2013, lets Windows 8 PCs play DVDs.
1/10th -- The amount a Mac owner spends to upgrade five machines compared to what a Windows user pays to do the same. Unlike Microsoft, Apple lets customers install Mountain Lion on as many as fivel personally owned machines.
1 -- The number of choices Windows and Mac users have for their upgrade editions.
Although Apple has long practiced one-size-fits-all, Microsoft followed suit for the first time this year when it offered only Windows 8 Pro in both the $14.99 and $40 deals. Previously, Microsoft has provided multiple upgrade versions so that, for instance, someone running Vista Home Premium upgraded to Windows 7 Home Premium, not to Windows 7 Professional.
2X -- How much more Windows users will pay for their upgrade to Windows 8 Pro than Mac owners will pay for theirs to OS X Mountain Lion.
3 -- Number of previous versions of Windows that can be upgraded to Windows 8 Pro: XP, Vista, and Windows 7. That's one more than either Vista or Windows 7 covered. Vista's upgrade was available to Windows 2000 and XP machines, Windows 7 to XP and Vista PCs.
Also the amount of free space on a USB flash drive necessary to create bootable installation media for the Windows 8 Pro upgrade, useful as backup install media or to do a "clean" install by wiping the hard drive before upgrading.