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
Oberon (operating system) Nieder's Oberon V4, which also shows difference between the different V4 implementations. Since 2013 this page moved to/is mirrored at SourceForge. V4 is closer to what would now be called an integrated development environment than an operating system of its own. There were many extensions written for V4, which are still available from the ftp server of SSW at JKU; some documentation can be found on their web-pages, more information is normally included in the packages and it is given in Oberon's special rich text format. The computer science department at ETH Zurich has in recent years begun exploring active