Many Linux's beginners are not cleared between Linux and X, what is the relationship between X and XFree86, X and KDE, GNOME, etc., often confuse concept, I want to explain X, X11, The relationship between Xfree, WM, KDE, GNOME, and the like. Because the level is limited, it may have a mistake, please correct it.
First, Linux itself has no graphical interface, Linux current graphics interface implementation is only implemented under Linux.
The graphical interface is not part of Linux. Linux is just a command line-based operating system, Linux and XFree relationships are equivalent to DOS and Windows 3.0, and Windows 3.0 is not an independent operating system. It is just DOS expansion, Is the application level system under DOS, not an independent operating system, the same XFree is just an application under Linux. Not a part of the system, but the X's is convenient for users to use the computer .Windows95 and later version The same, their graphical interface is part of the operating system, the graphical interface is implemented in the system kernel, no graphical interface Windows is not Windows, but Linux is different, there is no graphical interface Linux or Linux, many linux The web server is not equipped with a X server at all. This is also one of the important differences between Windows and Linux.
Second, X is an agreement, not a specific software:
X is an agreement, just like the HTTP protocol, the IP protocol, this concept, many beginners, even people who have a certain amount of people have a certain time, and a X-based application needs to run and display the content, and they start to use X protocol and server talk. For example, an X application is to output a round on the screen. Then he uses the X protocol to the X server: Hey! I need to draw a circle on the screen. X application is only responsible to tell the x server on the screen Where is the color painted for a lot of circles, and the specific "painting" action, such as this circle how to generate, what graphics card driver to command the graphics card to complete the work is done by the X server. X server It is also responsible for capturing the action of the keyboard and mouse. It is assumed that the X server captures the left button of the mouse being pressed. He tells the X application: Dear application gentleman, I found that the mouse was pressed, what did you have?
If the X application is designed to draw a square on the screen, then the X server says to the X server: Please draw a square, of course, what color paintings do he tells the server? How big is a square, but it doesn't care how to paint - that is the server.
Then the agreement is required to be realized, this is what I want to say:
Third, X and XFree86 relationship.
With the agreement, the specific software needs this agreement. Just like the traffic police, the traffic police needs the traffic police to maintain the traffic order. Xfree86 is such a "traffic police" to implement the agreement according to the regulations. He follows the X protocol. The rules are ruled to complete the task displayed on the screen submitted by the X application. Of course, it is not only a particular traffic police to maintain and implement this regulation. For example, it can also be implemented by the traffic regulations. When necessary, the police It can also be intervened, of course, the premise is that they must understand traffic regulations, that is to know the agreement. So the software that implements the X protocol is not only XFree86, XFree86 is just a free X server software for the X protocol.
Commercially used Motif, now there is xorg, there are many small X server software written by the love number. You can even have X servers on Windows so you can run a X application on Linux system. Then it is displayed on another Windows system. How bad can you find such X server software with Google.
The most common use on Linux is Xfree86. By the way, Apple's graphical interface is also the X protocol, and is considered to be the best X protocol graphical interface, and his implementation of the X protocol is The system core is in the system, so the performance is much better, which is why many large three-dimensional graphics design software is on the Apple platform.
To make it easy to understand the HTTP protocol comparison:
Agreement is http (Hyper Text Transmission Protocol)
Realizing this protocol is: Apache IIS, etc.
Customers requested for these servers are: IE, Mozilla, Netscape, etc.
What is the relationship between X and X11R6?
I don't know if the beginner has noticed / usr / x11r6 this directory, this is the default installation directory of Xfree
X11R6 is actually the meaning of X Protocol Version 11 Release 6 (X-Agreement, the sixth release of the sixth release), that is, the X protocol currently used is 11th edition, and then 6 small corrections. Different versions of X The agreement cannot be communicated. Just like we now IPv4 and IPv6 cannot communicate, but don't worry, now the X server software and X applications follow X11R6.
In addition, XFree86 3.3.6 Xfree86 4.3.6 and other versions are the version number of software Xfree86 for implementing the X protocol. This is the concept of beginners often confused.
The version of the protocol version and the software that implements the protocol - the difference between these two concepts, do you divide it?
5. What is the relationship between X servers and WM (Window Manager Window Manager).
How do you start the graphics interface?
If you are an open graphical interface, it is too regrettable. It should be a good time to know the X server startup process. But it doesn't matter. You open an xterm input:
INIT 3
You can safely return to the character interface.
Ok, wait until the following experiments you fully understand what is related between X and WM (Window Manager Window Manager).
Enter the following command:
#startx
The startup graphics interface, you see a peaceful time use of the same full graphical interface operating environment.
You can maximize, minimize, move, turn off the window.
Press CTRL Alt Backspace to reverse the character interface.
enter:
#xinit
Start the graphical interface again, what you saw, you see an xterm. And you can't move. But you can enter the command in this xterm to open the X application, such as I entered:
#mozilla
Open your browser, what is the difference between the browser you see? He can't move in the middle of the screen, can not minimize, no maximize, no border.
Why is the same X application that doesn't have this? Because we also launched a WM (ie window manager) while we use the StartX boot graphics interface, if you start KDE with KDE, if you start using gnome GNOME. But you didn't start WM when you start the graphical interface with the xinit.
Now you understand the role of window manager? His role is to maximize, minimize, move, close windows, etc., and these are not the X server to be done.
If you start the graphical interface with the xinit and enter TWM in XTerm, see what will there?
XTERM is coupled with a border, you can maximize, minimize this xterm, and TWM is a self-contained window manager in Xfree86, which is a relatively simple window manager, but he has a window. All of the characteristics of the manager.
If you don't enter TWM, you can start GNOME.
Or enter the startKDE boot KDE.
You can clearly understand the relationship between them through the above experiments.
6. About KDE and GNOME
KDE and GNOME are the most common graphical interface operating environments in Linux, but they are not just a window manager.
KDE is an abbreviation for King Desktop Environment. He is not only a window manager, but also a lot of application software and convenient desktop environment, such as a taskbar, start menu, desktop icon, and more.
GNOME is the abbreviation of GNU Network Object Model Environment. Like KDE, it is also a powerful integrated environment.
In addition, in other UNIX systems, CDEs are often used as such an environment.
Other small window managers are:
Window Maker, After Step, Blackbox, FVWM, FVWM2, and so on are all common window managers. Reredhat9 has Window Maker but the default is not installed. You can put it back. As long as xinit is again wmaker & you can use WindowMaker.
Seven, Linux graphical interface hierarchical relationship summary
Linux itself -> x server -> window manager (integrated desktop environment)
