The kernel of Linux is responsible for handling all the interactions between CPU and outside world, deciding the order of all programs share the processor time, effectively managing hundreds or thousands of processes to share the limited memory available in system, skillfully planning the data transmission as a whole to save the time consumed by CPU on waiting for the slower hard drive. Therefore, in-depth study of the most essential parts of the Linux kernel lets you completely understand what makes Linux run normally and why it can work well in various system distributions.

CentOS (short for Community ENTerprise Operating System) is a free, open-source, enterprise-class and community-supported computing platform that derived from the same source code with Red Hat Enterprise Linux OS. At present, there have been increasing Internet services or applications around the world that require high stability (including a variety of purposes of servers and business applications) are running on it, rather than RHEL.

Remix OS (short for Remix Operating System) is an Android OS based on Android-x86 Open Source Project (AOSP) through deep customization and secondary development. It was started by 3 ex-Google engineers from China, written in C (core), C++, Java (UI). Remix OS for PC allows users to run Android mobile apps/games on any Intel-based PC, and mainly uses tablet PC, all-in-one machine, smart display as its carrier at present.

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.

Since Red Hat published its last one (9th) release (Red Hat Linux 9) in 2003, they decided not to provide free technical support & product certification any more, and fully turned to the development of Red Hat Enterprise Linux (RHEL for short). This made some Red Hat rebuilders (open-source Enterprise Editions, such as White Box Enterprise Linux, Tao Linux, X/OS Linux, Scientific Linux) were born at the right moment. The most active one is CentOS (short for Community Enterprise Operating System).