The document presents on mobile operating systems. It discusses what a mobile OS is and how it controls functions on a mobile device like keyboards, messaging, etc. It outlines some of the main mobile OS's like Java ME, Symbian, iPhone OS, Windows Mobile, and Android. It provides brief descriptions of some of these operating systems, including that Symbian OS is 32-bit and multitasking, Windows Mobile provides interoperability, and Android is based on Linux and allows app development using Java libraries. It notes that while many OS's competed in the past, Android is now dominating the mobile market share.