Hi guys. Welcome to Linux Series Courses from Alibaba Cloud. In this series courses, we will have a comprehensive knowledge about Linux operation system. Today is the first class. In this class, we will give a brief introduction to Linux operation system. Now, let's get started. First section, Linux Introduction. In 1986, Andrew Tanenbaum created MINIX. MINIX as a minimal Unix-like operating system [inaudible] students and others who wanted to learn the operating system principles. In 1991, Linux Torvalds created Linux, released source code on Internet. While attending the University of Helsinki, Torvalds became curious about operating systems, frustrated by the licensing of MINIX, which at the time limited it to educational use only. He began to work on his own operating system kernel, which eventually became the Linux Kernel. With development of the Internet, Linux systems have rapidly spread. In 1994, Linux Kernel 1.0 was released. In the same year Red Hat was founded. In 1996, Linux Kernel 2.0 was released. In 2003, Linux Kernel 2.6. was released. In 2011, Linux Kernel 3.0 was released. In 2015, Linux Kernel 4.0 was released. Linux operating systems is used in the following application scenarios. First, desktops and laptops. According to web server statistics as of June 2016 that estimated market share of Linux on desktop computer is around 1.8 percent. Second, web servers. [inaudible] publishes statistics that use the top one million hardware domains, which as of May 2015 estimates that 96.55 percent of web servers from Linux. Third, mobile devices. Android, which is best on the Linux Kernel has become the dominant operating system for smartphones. Fourth, film production. For years, Linux has been the platform of choice in the film industry. The first major film produced on Linux servers was 1997's Titanic. Fifth, use in governments. Linux distributions have also gained popularity with the various local and national governments. Here are the popular distribution of Linux. First, Red Hat Linux. One of the original Linux distribution. The commercial non-free version is Red Hat Enterprise Linux, which is aimed at big companies using Linux servers and desktops in a big way. Second. Debian Linux. A free software distribution popular for use on servers. However, Debian is not what many would consider a distribution for beginners, and it's not designed with ease of use in mind. Third, SuSE Linux. SuSE was recently purchased by Novell. This distribution is primarily available for pay because it contains many commercial programs. Although, there's a stripped down free version that you can download. CentOS Linux, is derived from the Red Hat Enterprise Linux sources. The major difference between Red Hat Enterprise Linux, and CentOS is the port with RHEL you benefit from official Red Hat ports. On the contrary, since 2004, CentOS has enjoyed a massive community-driven force system. Now, let's come to the second section. Linux Operation System Architecture Introduction. From the layout, we can see that Linux operation system a picture can be divided into three parts. First, kernel. The part of the OS where the real work is done. Second, system call interface.It comprise a set of functions often known as API, that can be used by the applications and the library routines to use the service states provided by the kernel mobile device. Third, application user's interface. It's the interface between the kernel and user. It allows users to make comments to the system, and it is divided into text based and graphical based interfaces. Linux operation system architecture includes the following directories. Root directory, it's top of the file system. /sbin, the directories /sbin contains system administration tools utilities and general root only commands such as hault, reboots and shutdown. /etc, it contains host-specific files and directories. For example, information about system configuration. /dev, it contains a specific files for devices, for example fd0, hd0 and so on. /proc, it contains process and system information. /var, it contains data that keeps on changing as the system is running and system logs like /var/log/messages. /tmp, it contains temporary files. Usually, files in this directory will be deleted from time to time to avoid the system fills with temp files. /usr, one of the largest collections of that Linux file system. /home, it contains the home directories of every user in the system. /boot, it contains all the files needed to boot on Linux system, including the binary of the Linux kernel. /lib, it expose all essential libraries of different languages compilers. /opt, it is used to install on software packages. Systems start and stop. The Linux operation system has seven levers. We usually use level 3 and level 5, and the foreign comments and many use to shut down the system in different cases. You may be curious about how to get a Linux environment where there are many ways, such as installing Red Hat on your own laptop creating a virtual machine on your silver with 2C. Now I will show you an easier way to get a Linux environment. First log in alibabacloud.com, then Console. You will attempt to use a homepage. You then click Elastic Compute Service. Then click Instances and create instance. For billing method, you can choose according to your demands. For region, Alibaba Cloud can provide wide world services. You can choose the region which is close to your location. Image item, we can choose Linux image. For example, CentOS 6.8. Since we just want to create a Linux environment quickly, we can use that 34 seconds. We need a public IPv4 ECS so we can remote log in this Linux environment. After creating ECS, reset the password of server by manual. After resetting password, the server needs to be restarted. After restarting the server, we can use PuTTY to remote lock in this ECS server. Now let's open PuTTY. Now open PuTTY. Input IP address and password. Now we log in the ECS server which we created, and the OS is CentOS 6.8. It is a Linux OS. Thanks. That's all of the course. Thank you.