<P> There are "three big personal computing platforms ." Google claims over 2 billion users with Android while Microsoft has claimed over 1.4 billion users for Windows . The third "platform"--or strictly two (or three) platforms--Apple's iOS and macOS combined, is claimed to have over 1 billion users . Windows running on personal computers (i.e. those other than e.g. smartphones, such as desktop computers) has been dominant for over 25 years period since the early 1990s . The mainframe computer - era preceded the desktop era . From late 2016 the mobile era took over, with total desktop computers' market share (measured by web usage and including macOS) having reduced to 45% by January 2017 . The "end of an era" was declared by StatCounter with Windows no longer the most popular operating system, and desktop computers in general no longer the most popular format . Since 2017, smartphones alone--excluding tablets--have been the most common computing device globally . </P> <P> Different categories of computers use a wide variety of operating systems (OSs). Windows gained the majority usage share in the 1990s on desktop computers, or personal computers (PCs), the type of computer that was then taking over . It was eventually described as "dominant", and it is still used by the majority of desktop machines, but it is no longer dominant across all platforms, although the latest version can run on all platforms . On smartphones, Android is dominant by any metric . Its installed base is over 2.6 billion (and 0.6 for iPhones) according to Statistica which tops Windows on PCs worldwide . No operating system has a clear majority on all platforms or in all regions, but Android has surpassed Windows globally across all platforms, by StatCounter's web usage statistics, a proxy for all use . Android is the highest ranked OS in most countries of the world . When Android's is added to the usage shares of other mobile operating systems such as Apple's, in late 2016 the world became smartphone - majority . Android has over half the usage share across all platforms in the two biggest and most populous continents, Africa and Asia . Windows is still dominant on desktops everywhere but as of September 2017 when compared across all platforms it's below 50% on every continent or at least when not always, then on weekends . It is down to 36% in North America and 48.27% in Europe . The Windows share across all platforms in the United States was down to 36.34% (the total US desktop share just under 50%) and 40.18% in the UK . </P> <P> Since 2013, devices running Android have been selling more than Windows, iOS and macOS devices combined . Android has therefore become the most popular operating system on smartphones, while iOS is more common on tablets . Most desktop and laptop computers still use Microsoft Windows, while virtually all supercomputers use Linux and have done for over a decade . Among server computers, there is more diversity with Linux and Windows Server most popular, and many fewer mainframe OSs . </P> <P> Data about operating system share is difficult to obtain, since in most categories there are few reliable primary sources or agreed methodologies for its collection . </P>

What is the most popular operating system for servers
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