As such it is one of the simplest possible models of computation. Nevertheless, there is an elementary cellular automaton (rule 110, defined below) which is capable of universal computation.
In 2012, there were some 3,997 distinct Android devices. This year there are a whopping 11,868. Eight versions of Android are currently in use and 37.9 percent of users are running Jelly Bean, the latest version of the mobile OS. Samsung's apparent share of the market is 47.5 percent.
Manufacturers can decide to change layout and behaviour of the system. So users may experience different ways of doing things. One such example is the handling of the Menu button. Google changed the design from Android 3 (for tablets) and Android 4 (for phones). So some Android devices may have a dedicated menu button, others don't. This make it a bit challenging to write a guide like this for Android beginners. We also have the situation when older Android devices get the Android 4 upgrade, they of course already have the dedicated menu button.