Linux, how much do you know!

1. Linux Overview  

Linux is a free and open source Unix -like operating system. Strictly speaking, the term Linux only represents the operating system kernel itself, but usually uses the Linux kernel to express that meaning. Linux is often used to refer to a full operating system based on the Linux kernel, including GUI components and many other utility tools. Since these user-space-enabled system tools and libraries are primarily provided by the GNU program launched by Richard Stallman in 1983, theFSF proposes to name the combined system Gnu/linux, but Linux is not part of the GNU program, So the name doesn't get the consensus of the community, but we can't forget the GNU campaign's drive to Linux. In addition, any individual or institution is free to use all the underlying source code of Linux, as long as the GNU General Public License is followed.

* Professional Terminology

Unix	A computer operation system with multi-tasking and multi-user characteristics. In 1969, Bell Labs at the US-at-t company was developed by Ken Thompson.
gui Component	tools that support graphical desktops
gnu plan	gnu Program (English:
FSF	Its main work is to execute gnu plan to develop more free software
GNU general Public License	also called LGPL Agreement is the norm that people must follow to use open source code

2. Linux Development

Linux, which is more focused on system security and performance, will be taken seriously by abandoning the ornate graphical interface. Slowly, some individuals and businesses developed third-party non-GNU components also began to provide support for the Linux kernel, including a large number of kernel modules, user applications and libraries and other content. Linux communities or businesses are starting to roll out some important Linux distributions.

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3. How Linux Works

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Linux at the bottom of the same is a variety of hardware, CPU, memory, etc., working on the hardware of the kernel is the entire Linux operating system is the most important link, the importance of the following detailed description. The kernel is a variety of applications, and also includes a very important shell interface, the application through the shell implementation of the hardware, which can be likened to the Windows click event.

  Here's how the kernel is important throughout the system: applications that want to leverage the computing power of the underlying hardware must have an application program to drive hardware, and applications on the upper level must go through compile , Can be converted to binary code that the computer recognizes. means that any application that wants to run requires not only a complete set of drivers, but also a compiler. You know, the each CPU has its own set of instructions, which determines the different libraries that are called at the top. Even if you do a program to complete the driver and compile, when the program for another platform , not only the compilation needs to be restarted, and the original driver will also lose meaning, the program portability greatly reduced. So there is the kernel, which through the system call (Systemcall) to isolate the different applications to different vendor CPU dependence, and itself provides a powerful compilation function, the program will have a better compilation environment. So, how did the upper-level application write, using the countless 0 and 1? or directly take advantage of the system call provided by the kernel? Obviously impossible, these original programming interfaces, I believe only the ashes of engineers will call it! The kernel then comes in handy again, encapsulating the system call once more, becoming a library call, and then having BIF (built-in functions) that can be called directly by the application. On top of that, a large number of applications have been created, and a complete Linux operating system can work well.

4. Linux Status

today's various There are various Linux distributions available, from embedded devices to supercomputers (super computer), and in the server domain, typically using a lamp combination. Home air-conditioning, smart watches, mobile phones, aviation, most of the system equipment are using Linux, although most people still do not know about Linux, but it did come into our lives, I believe that the future of Linux will be more beautiful.

This article is from the "dmwing" blog, make sure to keep this source http://dmwing.blog.51cto.com/11607397/1832534

Linux, how much do you know!