Today I am going to talk about mobile operating systems that use Linux kernel. Some good examples are Maemo, MeeGo (Maemo's derivative), Firefox OS, Ubuntu Touch and Android. Maemo and MeeGo Maemo appeared in 2005 as OS2005 and the only device running it was Nokia 770 Tablet. However, tablets weren't as popular as nowadays and this one received many complaints about slow CPU, size of the on-board memory (64 MiB), short battery life (four hours only). So, generally it didn't succeed. Several years ago, in 2009, Nokia introduced N900, running Maemo 5, which is highly customizable, fast and functional. Although, there were some problems with hardware, this operating system is very interesting. In 2010 Nokia created N9 with powerful hardware and MeeGo on board. It is fast, simple and easy to use and perfectly looks on N9. Linux project on Nokia seems like has no future after many issues with Microsoft and developing Windows Phones. Even though they introduced Nokia X this year, it is far from what we saw in Maemo and MeeGo. It's a pity. Firefox OS Firefox OS introduced in 2012, it is based on Gonk, Gecko, XULRunner and Gaia. I found very interesting devices made by GeeksPhone, in particular Revolution, but it seems a bit buggy and slow, though the hardware is tough enough. The idea is good and it will be a lot of work, GeeksPhone is the official developer of Firefox OS. Ubuntu Touch Fast, user-friendly, its functionality is much cooler than in Windows Phone and iOS. Though there are official developers, everyone that uses Android can install it. It is very interesting and probably has a nice future because the Community helps in developing and Canonical support really exists. Introduced in 2013 (as beta) and in 2014 (as alpha with Ubuntu 14.04). Android The first version appeared in 2008 and the first smartphone running it was HTC Dream. The latest versions of Android looks very fine, functional and customizable. No problems with developing - Google does it very well. Each project is very interesting. The first ideas did not succeed because Nokia abandoned Linux project in favour of Windows Phone. After acquiring Android Inc. in 2005, Google has been successfully developing Android, which is now the most popular mobile operating system.