Microsoft, especially, has been talking up fragmentation, or the reduction of fragmentation, among its Windows users as it beats the Windows 10 drum.
"Today Windows customers are spread across many versions. This fragmentation makes it challenging for developers to delight our customers with applications," said Terry Myerson, the Microsoft executive who leads the Windows group, in January when he announced that Windows 10 would be a free upgrade for consumers and some businesses.
In fact, Microsoft has set an ambitious goal of getting Windows 10 onto 1 billion devices -- or two-thirds of those currently running Windows -- by mid-2018, part of its anti-fragmentation strategy as it pivots toward making money from services and apps.
Windows is much more fragmented than is OS X, of course: As of April, about 17% of all Windows PCs ran 2001's Windows XP, more than the share of Windows 8/8.1, Microsoft's newest OS. And unlike Apple's most popular edition, Microsoft's was 2009's Windows 7, which accounted for 64% of all in-use Windows versions.
Operating systems on personal computers have a long "tail," something even Apple has found out.
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