Introduction to Linux applications and development

Introduction to Linux applications and development

Linux has been learning for some time, but also a deeper understanding of the Linux system, today to summarize what is the Linux system, as well as a brief introduction of the Linux system history and the current enterprise level of application.

As the name implies, Linux is a system (OS), but more professional speaking it is a kernel, we call it the operating system, it is a kind of free and open source Unix-like operating system, for the Linux operating system may be unfamiliar to many people, Most of the non-undergraduate-born people just heard the name, but they do not know what the system is. In fact, we use the Andriod system is the Linux kernel, and the Android phone is open source, and Apple uses the ISO system using the UNIX operating system, UNIX operating system is a more ancient than Linux commercial operating system, So Apple's iOS system is also closed-source.

The kernel of the operating system was first released by Linus Torvalds on October 5, 1991. After countless programmers add code to it, plus the user-space application, it becomes the Linux operating system. Linux is also the most famous example of free software and open source software development. As long as the GNU General Public License is followed, any individual or institution is free to use all the underlying source code of Linux, and can also be freely modified and republished. Most Linux systems also include programs such as X window, which provides a GUI interface. Most people use the Linux distribution directly, rather than choosing each component or setting up their own. Of course, there will be some experts and geeks will choose to assemble their own operations, starting from the source of source code compilation and system components reorganization.

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 were primarily provided by the GNU program launched by Richard Stallman in 1983, the Free Software Foundation proposed to name the combined system Gnu/linux, but Linux was not part of the GNU program.

Linux was originally a free operating system for PCs that supported the Intel x86 architecture. Currently, Linux has been ported to more computer hardware platforms, much more than any other operating system. Linux can run on servers and other large platforms, such as large hosts and supercomputers. More than 90% of the world's 500 fastest supercomputers run Linux distributions or variants, including the fastest top 10 supercomputers that run on Linux kernel-based operating systems. Linux is also widely used in embedded systems, such as mobile phones, tablet tablets, router router, TV TVs, and video game consoles. The Android operating system, which is widely used on mobile devices, is created on top of the Linux kernel.

The general user benefits from the GNU GPL and LGPL protection, which can be used to obtain complete Linux from different pipelines, so Linux can be "free (gratis)". Linux is cheap and inexpensive compared to UNIX's expensive copyright fees.

The development of Linux

The development of recent years has made Linux another big rival for Microsoft. Linux with its low price, good quality and stable competitive advantage, is invisible to the proliferation of many PC-based work platform. Because of the lack of commercial application software, it is impossible to penetrate the mainstream operating system of the general merchant because of the tool program with strong academic flavor. However, today's Linux is non-defeating, KDE, Gimp, GNOME and other plans to carry out successively, for X to provide more graphical interface of the desktop operating environment and application software.

About 1993 years ago, Linux first appeared in the form of release software (distribution). This is a complete set of software, including installers, cores, applications, X, drivers, and other software packages, downloaded to disk for installation via the Internet. At that time, the installation process was simple, difficult to install properly, insufficient interface affinity and poor hardware support is the biggest obstacle.

Later, the optical drive, CD-ROM media also came into being, and now the distribution software produced by Linux manufacturers are mainly issued by this medium. There are three kinds of red Hat, Slackware and Debian that are common in China. Among them, Debian is still a non-commercial type of heavyweight distribution software, the FSF has been a fund to help the development of its initial stage. Anyone can download the entire release software from the Debian FTP station.　　   Of course, a business organization like Red Hat can be downloaded from an FTP station just like Red hat, but if you spend a little bit of money on discs, you get additional technical support and useful documentation. The easiest way to get these discs is to buy books on Linux, whether in Chinese or English, with a copy of the release software on the back containing the company or organization. The general book will have a special chapter to explain the installation and set up the process, readers can be good use. Different distribution software has different installation mechanisms, but it is all Linux.

For domestic users, the most concern is the development of Linux Chinese technology. X Window System has a stable Chinese version, a variety of Chinese input method and the Chinese simulation window has entered a mature stage, I believe the future will be toward the application of the cultural development of the software, so that x operating environment in line with the needs of domestic users.

application of Linux

Without business activities, there is no Linux, no freedom of information, and it is impossible to have Linux.

In addition to being an excellent software development platform, Linux is also a good partner for work and home. Some people say: "With Linux, it is equal to have the lamp of Allah." "This is not false. Others say: "There is no software that has been ported to Linux, and there is certainly no value at all." "That's not a bad word."

The development of Linux confirms the tendency for information to become cheaper and the market expands indefinitely because it is cheap. Business activities are also turning to service-oriented patterns. The most straightforward case is the application of the ISP.

Linux can be used to erect isp!

The publisher of the Linux Journal SSC (Specialized System Consultants) is based on Linux as the network Dial-up service platform. To become an ISP, you need to have the ability to connect to the Internet, multi-sequence FU-dial services (such as software systems provided by companies such as Cycades, Maxspeed, Gtek, etc.), PPP and slip services, Usenet newsgroups (such as inn), mail delivery (such as SendMail) , Web server (such as Apache), backup functions (such as tar, cpio), and so on application software. From this observation, the main control costs will fall on the internet communication rental fees, the cost of investing in Linux is very low.

In addition, Linux has the following features:　　

· Multi-tasking: This means that Linux can serve the needs of many people in the same period of time. In a word, you can listen to the Titanic's soundtrack CD, edit the paperwork while you print the file, and play the X version of Tetris at any time.

· Multi-CPU Support: This is definitely not an NT patent, Linux also supports this hardware architecture, representing faster operations and revolutionary algorithms will become the mainstream of the Times.

· RAM Protection mode: The program (processes) does not interfere with each other, to ensure that the system can work long and correct. According to many people downloading the system Assessment Program (benchmarks) to test the performance of Linux, the results found that only with 486CPU pc, the performance will be comparable to the sun or Dec intermediate workstations.

· Dynamic Loader: When the program loads RAM execution, Linux only loads the relevant program modules on the disk, effectively increasing the rate of execution and the management of RAM.

· Dynamic Link Sharing Program Hall: This means that the size of the execution file is greatly reduced, helping to conserve disk space.

· Support a variety of file systems: such as Minix, Xenix, System V and so on the famous operating system. Future NT NTFS will also be included in the support.

· See DOS: This is so-called transparency (transparency); The DOS FAT file system is considered a special remote file system that can be used flexibly without any special instructions, just like a directory that exists under Linux.

Excerpt from "official CLE 0.8-Chinese Linux Extension Package usage guide

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Introduction to Linux applications and development