Kali Linux (successor of BackTrack Linux) is a free and open-source Debian-based Linux distribution funded and maintained by Offensive Security from Switzerland. Users can boot and use this OS via hard disk, live CD or live USB anytime and anywhere. Almost all open-source tools used for digital forensics, penetration testing, ethical hacking and network security assessments are included. There is no need to prepare and maintain this Linux distribution (including gathering all those software and their dependencies) by yourself, or to install any software and save any files on Kali.

After all, Google is the first company attempted the localization of Android on PC. Whereas, they missed the era of mobile Internet & network and smartphone sweeping around the world due to an early start. Subsequent years, Android-x86 appeared first and lay a solid foundation for newcomers to make transition. Then it's Phoenix OS and Remix OS's turn to break a new ground. AppNee thinks that: the day Android rooted on a PC platform (that means compatibility is no longer a major problem), the time Linux started to formally replace Windows in all directions!

Android-x86 (AKA: Android X86) is an unofficial Android Open Source Project (AOSP) started in 2009 by Chih-Wei Huang from Taiwan. The main purpose of this project is to provide a complete and feasible set of Android system solutions for X86 PC platform, including a whole set of source code tree, supporting documents, as well as Live CD and Live USB.

Windows XP SP4 Unofficial, as its name says, it's not a Service Pack released by Microsoft Official site, but it is so popular that XP's loyal supporters call it SP4 of Windows XP after the official final one - SP3.