1、 Introduction of Linux system
Linux is a set of UNIX like operating system which is free to use and spread freely. It is a multi-user, multi task, multi thread and multi CPU operating system based on POSIX and UNIX. It can run the main UNIX tools, applications and network protocols. Supports 32-bit and 64 bit hardware. Linux is a stable multi-user network operating system, which inherits the design idea of UNIX with network as the core.
There are many different versions of Linux, but they all use the Linux kernel. Linux can be installed in a variety of computer hardware devices, such as mobile phones, tablets, routers, video game console, desktop computers, mainframes and supercomputers.
Strictly speaking, Linux operating system refers to “Linux kernel + all kinds of software”. The word Linux only means Linux kernel, but in fact, people are used to using Linux to describe the whole Linux kernel based operating system, and use GNU engineering tools and database operating system.
2、 The origin of Linux
1. The birth of ideas
As we all know, Linux kernel was first designed by Linus Torvalds. In 1988, towaz entered the University of Helsinki and enrolled in the Department of computer science. In school, because of the need of study and my interest, I came into contact with the UNIX operating system. At that time, Helsinki had only one latest UNIX system, but it was still difficult to meet the needs of towaz. Therefore, he thought of writing a UNIX like operating system. Soon after, Torvalds learned that Professor Tan Ningbang wrote the MINIX system for educational needs. Make your thoughts more firm.
2. Start designing
In early 1991, Linus Torvalds bought the latest Intel 386 personal computer, installed the MINIX system, and began to learn the MINIX operating system. Through the source code of MINIX system, I learned a lot of design concepts of kernel programming. In April 1991, Linus Torvalds began to develop his own operating system.
3. Share and modify
When he found that his writing could run smoothly on 386 and read MINIX’s file system, he placed the kernel program on Finland’s largest FTP network for you to download. At the same time, he posted a message on BBS, hoping to get some suggestions for modification. Therefore, when users install and use, they will feed back problems to towaz. Within the scope of the problems Torvalds can solve, he can quickly update and debug the Linux kernel.
At the same time, in order to make his Linux compatible with UNIX system, and make all software can be executed on Linux, Torvalds began to refer to the standard POSIX specification.
POSIX is the abbreviation of portable operating system interface, which focuses on standardizing the interface between core kernel and application program. It is a standard issued by American Institute of electrical and Electronic Engineers (IEEE)!
4. The majority of fans to join
After all, one’s power is limited. Some of the hardware could not be obtained by tovaz, so it was impossible to write the relevant driver. At this time, volunteers came forward to help write the driver. And Torvalds is very pragmatic. As long as the test can run, the program code will be added to the kernel. Because of this situation, the development of Linux is gradually modularized, and the maintainability is also greatly increased.
Later, because the Linux kernel added too many functions, it was too hard to rely on Torvalds alone to carry out the actual test of the kernel and add the kernel source program, so many friends jumped out to help. For example, Alan Cox, Stephen Tweedie and so on, these important deputies will first test the volunteer’s patch or new function code, and upload the results to towaz to see, let towaz do the selection and integration of the source code added to the final kernel! This hierarchical responsible result makes Linux development easier!
It is particularly noteworthy that these Linux development assistants of Torvalds and hacker volunteers who voluntarily send patches have never met, and they are distributed in every corner of the world. We all work together to develop today’s Linux.
5. Release of Linux official version
In 1994, this group of virtual teams finally completed the official version 1.0 of Linux kernel. There are 170000 lines of code. This version also adds X window system support! In addition, towaz pointed out that penguin is the mascot of Linux.
In June 1996, Linux 2.0 kernel was released, which has about 400000 lines of code and can support multiple processors. At this time, Linux has entered the practical stage, and there are about 3.5 million people in the world using it.
3、 Open branches and scatter leaves
1. The generation of different distributions
Because Linux has joined the GNU program, anyone can get the source code and execute the kernel program, and can modify it. And because GNU’s GPL license is not unable to engage in commercial activities, many commercial companies and teams are dedicated to developing their own Linux distribution. More famous are red hat, SUSE, Ubuntu, Fedora, Debian, CentOS, etc.
2. Support standard of different distribution
A lot of people can’t help worrying about whether so many distributions will be different? I can tell you that there is no need to worry, because these versions use the same kernel, and there are Linux standard base (LSB) and file system Hierarchy Standard (FHS) of directory architecture to regulate developers. The only difference between them may be the management tools and suite management mode developed by the developer himself.
So, basically, except for the rigor of the architecture and the content of the selected suite, each Linux distribution is not very different. You can choose your favorite distribution to install!