This document provides an overview of mobile operating systems including their history, common systems like Android, iOS, Blackberry and Windows, and a comparison of their key capabilities and costs. It outlines that the first mobile OS was in 1979 for embedded systems in phones, with major developments like Palm OS, Symbian, iOS and Android emerging between 1994 to 2008 which helped drive smartphone adoption. The four major mobile OS today are Android, iOS, Blackberry and Windows, which differ in aspects like licensing, app stores, default applications, and developer costs.