This document presents a comparative study of different mobile operating systems conducted by students Zulkar Naim, Mosarrof Hossain, and Shahidul Islam. It provides overviews of BlackBerry OS and Symbian OS, compares app availability and market share between various platforms, discusses advantages and disadvantages, and examines recently launched and upcoming mobile OSs such as Firefox OS and Ubuntu Touch. The study was supervised by Nafisa Khanam Siddika and presented course research on comparative analysis of mobile operating systems.