Android (operating system) store, and by September 2013, one billion Android devices have been activated. , the Google Play store has over 2.7 million Android applications published, and , apps have been downloaded more than 65 billion times. The operating system's success has made it a target for patent litigation as part of the so-called "smartphone wars" between technology companies. Android devices account for more than half of smartphone sales in most markets, including the US, while "only in Japan was Apple on top" (September–November 2013 numbers). At the end of 2013, over 1.5 billion Android smartphones have been sold in the four
Smartphone when the cover is closed, it protects the screen. Some "book"-like cases have additional pockets for credit cards, thus enabling people to use them as wallets. Accessories include products sold by the manufacturer of the smartphone and compatible products made by other manufacturers. A mobile operating system (or mobile OS) is an operating system for phones, tablets, smartwatches, or other mobile devices. Mobile operating systems combine features of a personal computer operating system with other features useful for mobile or handheld use; usually including, and most of the following considered essential in modern mobile systems; a touchscreen, cellular, Bluetooth, Wi-Fi