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
Copland (operating system) its window. Programs that are not in the foreground are periodically given short bits of time to run, but as before, the entire process is controlled by the applications, not the operating system. Because the operating system and applications all share a single memory space, it is possible for a bug in any one of them to corrupt the entire operating system, and crash the machine. This is not particularly annoying under a single-application model, in which case the application crashes anyway. But under MultiFinder, any crash will crash all the other running programs as well. The multitasking of multiple