The development of Linux

Briefly

Linux is a set of free and open source Unix-like operating systems, born on October 5, 1991 (the first officially announced), by the Finnish students Linus Torvalds and later joined the many enthusiasts jointly developed.

Linux is a POSIX and UNIX-based multi-user, multitasking, multi-threaded and multi-CPU operating system. It can run major UNIX tools software, applications, and network protocols that support 32-bit and 64-bit hardware. Linux inherits the design idea of Unix as the core of network, and is a stable multi-user network operating system.

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 consoles, desktop computers, mainframes, and supercomputers.

Strictly speaking, the word Linux itself only represents the Linux kernel, but in fact people have become accustomed to using Linux to describe the entire Linux kernel, and use the GNU engineering various tools and databases of the operating system.

The father of Linux

• Linus Torvalds (Linus Torvalds)

Linus Torvalds is known as the Father of Linux, a famous computer program clerk and Hacker. The inventor of the Linux kernel and the partner of the program. He uses personal time and equipment to create one of the most popular operating system cores in the world today, and is now employed in the Open Source development lab (Osdl:open Source Development Labs, Inc.) to develop the Linux kernel.

Linux is a peculiar operating system that is born in the network, grows in the network and mature in the network. In 1991, Linus Torvalds, a Finnish university student, developed the idea of developing a free UNIX operating system, when Linux was born, in order not to allow this fledgling operating system to fold, Linus Torvalds publishes its own work Linux over the Internet. From this a large number of well-known, unknown computer hackers, programmers to join the development process, a huge movement came into being, Linux gradually grew up.

Linux starts with the requirement that all source code be made public and that no one is allowed to profit from Linux trading. However, the ideal of pure free software is detrimental to the popularization and development of Linux, and Linux began to turn to the GPL, becoming a major part of the GNU camp.

Linux with excellent design, extraordinary performance, coupled with IBM, Intel, CA, CORE, Oracle and other internationally renowned enterprises support, market share gradually expanded, gradually become one of the mainstream operating systems.

Linux logo

Apple's logo is a bite of the apple, Microsoft's logo is a window (at least initially), and the Linux logo (mascot) is a penguin named Tux.

The source of the Penguins

1994 release of Linux Official Core 1.0, we want to Linus Torvalds think of a mascot, he remembered once in Australia, a zoo was bitten by penguins, simply Penguin as a mascot!

It is more acceptable to say that penguins represent Antarctica, and the Antarctic is a land of the world, and it does not belong to any country. This means that Linux is not owned by any commercial company, and is a technological achievement that everyone in the human race can share.

Sources of Tux

Most people believe that the name tux comes from Torvalds UniX, not because it looks like it's wearing an evening gown (tuxedo). There are also claims that tux from James Hughes:

Re:let ' s name the penguin! (Was:Re:Linux 2.0 really is
Released..) . James Hughes

Mon, June 1996 20:25:52-0400.

(T) orvalds (U) ni (X) –> tux!

Tux:linux mascot/logo Tux:linux mascot/logo

History UNIX

Unix operating system is a powerful multi-user, multi-tasking operating system, support a variety of processor architectures, according to the classification of the operating system, belong to the time-sharing system, the earliest by Kenthompson, Dennis Ritchie and Douglas McIlroy in 1969 at &t's Bell Labs developed. At present, its trademark rights are owned by the International Open Standards Organization, only UNIX systems that conform to the single UNIX specification can use the UNIX name, otherwise it can only be called Unix-like (unix-like).

Gnu

GNU is the father of free software, Richard Stallman, which was developed in 1984 as a software system based entirely on free software, with a corresponding generic public license (general publicly License, the GPL). Linux and a lot of software related to him were developed and released under the GPL.

The father of free software-Richard Stallman, like a solemn missionary, is buzzing around spreading the gospel of free software, explaining his dream of creating GNU: "The idea of freedom, not the free lunch". This free software "top priest" for his dream to spend most of his efforts, he not only created a lot of free software, such as: GCC, and GDB, in his advocacy, the current familiar with some software such as Bind, Perl, Apache, TCP/IP, etc. have become the classic of free software.

If Richard Stallman founded and facilitated the development of free software, Linus Torvalds to GNU Linux without hesitation, bringing the development of free software into a new realm.

Bsd

386BSD because legal issues were not released until 1992, NetBSD and FreeBSD were descendants of 386BSD, earlier than Linux. Linus Torvalds said that if there was a free 386-based unix-like operating system, he might not have created Linux. Although it is not possible to predict what effect this will have on the future software industry (if there is no such legal dispute, there is probably no revolutionary Linux today), one thing is certain that Linux enriches the soil.

Minix

Minix is a UNIX-like computer operating system based on micro-kernel architecture, invented by Andrew S. Tanenbaum. Minix was originally released in 1987, opening all the source code to university teaching and research work. 2000 re-changed to BSD licensing to become free and open source software.

Because of the policy change at/T, after the launch of version 7 Unix, new terms of use were released, the UNIX source code was privatized, and the UNIX source code was no longer available at the university. To avoid copyright disputes, the Professor decided to develop a UNIX-compatible operating system on its own, without using any of the source code, in order to be able to teach the details of the operation of the student operating system in class. He referred to it as a minix, with the meaning of small Unix (Mini-unix).

Minix no code to copy UNIX, so they do not have any inheritance relationship, Minix as the first open source operating system in the history of the internet after the short-term has been rapid development, a large number of people to download learning.

Since Minix is written by one of the professors, there are some loopholes. At this time, there are users found that the vulnerability exists, want to download some patches or write some patches to fix these vulnerabilities, repair found that the effect is good, and then suggested that the professor use these patches to improve the minix, the results, the professor is more stubborn, meaning: In order to maintain the purity of minix, No foreign code is required. In other words, it is not intended to do commercial distribution, so Minux maintained its most primitive demeanor.

Linux

In the next few years, because of the strong operation of the computer hardware industry, the Intel-led x86 system architecture of the personal computer, so the personal computer is quite a popular machine. But at this point, most of the people use DOS operating systems. At this time, a student named Linus Torvalds at the University of Helsinki in Finland did something unusual. At that time, he had a 386 computer, because he did not like the DOS system on his computer, so he thought: since Minix so good, so stable, then I would not transplant it to a personal computer (fortunately because Stallman advocated the open source concept, He was able to access some source Code, and through this idea, O (∩_∩) o~ He was very interested in reading the UNIX core, and remove the more complex core program, it can be applied to the general personal computer x86 system above).

By the year 1991, he finally put 0.02 version of the original code hobby on the network for everyone to download, because hobby by everyone's affirmation, quite a lot of friends put into this work. Finally, in 1994, the first full core version 1.0 was released and caused the current pandemic ... Because of the development of Linux kernel by the virtual team, we are all through the network to obtain the core Linux kernel source code, through their own careful transformation and then back to the Linux community, and then the development of a step-by-step completion of the complete Linux system, as for the Linus Torvalds is the initiator of this group. Thanks to this collective effort, Linus Torvalds Linux as the GNU licensing model for the same benefit!

Linux is Linus Torvalds influenced by Minix. But in the design philosophy, Linux and Minix big phase of the court. Minix uses the principle of microkernel in kernel design, but Linux is the same as the original UNIX with the concept of macro kernel. At the beginning of the development of Linux, the two sides also had a wonderful idea debate on the news group in 1992. Minix's authors and supporters argue that the single-core architecture of Linux is "a big setback to the 70 's", while Linux supporters argue that Minix itself is not practical.

Key Features

• Basic ideas

The basic idea of Linux is two points:

1. Everything is a document.
2. Each software has a definite purpose.

The first article in detail is that everything in the system boils down to a file, including: commands, hardware and software devices, operating systems, processes, and so on, which are considered to have their own attributes or types of files for the operating system kernel. Linux is Unix-based, largely because of the similarity between the two basic ideas.

• Completely free

Linux is a free operating system, users can be obtained through the network or other channels for free, and can arbitrarily modify their source code. This is not what other operating systems can do. Because of this, countless programmers from all over the world are involved in the modification and writing of Linux, and programmers can change them according to their own interests and inspirations, which allows Linux to absorb the essence of countless programmers and grow.

• Fully compatible with the POSIX1.0 standard

This makes it possible to run common DOS and Windows programs under Linux with the appropriate simulator, which lays the groundwork for users to go from Windows to Linux. When many users consider using Linux, they think about whether the programs that were common to windows before are working properly, which eliminates their doubts.

• Multi-user, multi-tasking

Linux supports multiple users, each user has their own special rights to the file device, to ensure that the user does not affect each other. Multitasking is one of the most important features of computers now, and Linux allows multiple programs to run simultaneously and independently.

• A good interface

Linux also has a character interface and graphical interface, in the character interface users can enter the corresponding instructions through the keyboard to operate. It also provides a x-window system similar to the Windows graphical interface that allows users to manipulate it using the mouse. In the X-window environment, like in Windows, it can be said to be a Linux version of Windows.

• Supports multiple platforms

Linux can be run on a variety of hardware platforms, such as the x86, 680x0, SPARC, Alpha and other processor platforms. In addition, Linux is an embedded operating system that can run on a handheld, set-top box, or game console. The Linux version 2.4 kernel, released in January 2001, has been able to fully support the Intel 64-bit chip architecture, while Linux also supports multiprocessor technology. Multiple processors work at the same time, which greatly improves system performance.

Linux kernel version

The Linux kernel uses three different version numbering methods.

1. Used before version 1.0 (including 1.0). The first version is 0.01, followed by 0.02, 0.03, 0.10, 0.11, 0.12, 0.95, 0.96, 0.97, 0.98, 0.99, and after 1.0.

2. Used after 1.0 to 2.6, the number consists of three parts "A.B.C", A represents the major version number, B represents the minor major version number, and C represents the minor last version number. A only changes when the kernel has changed greatly (only two times in history, 2.0 in 1994, 1.0, 1996). The number B can be used to determine whether Linux is stable, even b for the stable version, and the odd B for the development version. C represents some bug fixes, security updates, new features, and number of drives.

   In version 2.4.0, for example, 2 represents the major version number, 4 represents the minor version number, and 0 represents a minor change in the last version number. In the version number, the second digit of the ordinal is an even version that indicates that this is a stable version that can be used, such as 2.2.5, and the second odd version of the ordinal is usually something new to join, which is not necessarily a stable test version, such as 2.3.1. This stable version is derived from the previous beta upgrade version number, and a stable version is not developed until it is fully mature.

3. Starting with the 2004 2.6.0 version, use a "time-based" approach. Prior to version 3.0, it was a "a.b.c.d" format. Over the years, the first two digits a.b "2.6" remain the same, and C increases with the release of the new version, and D represents some bug fixes, security updates, additions to new features, and the number of drivers. After version 3.0 is the "A.B.C" format, B increases with the release of the new version, and C represents some bug fixes, security updates, new features, and drivers.

   The third way no longer uses even numbers for stable version, odd for the development version of the naming method. For example: 3.7.0 is not a development version, but a stable version!

Linux distributions

Linux is primarily used as part of a Linux distribution (often referred to as "distro"). These distributions are written by individuals, loosely organized teams, as well as business organizations and volunteer organizations. They typically include other system software and application software, as well as an installation tool to simplify initial installation of the system, and an integration manager that allows software to be installed and upgraded. Most systems also include programs such as XFREE86, which provide a GUI interface, that once ran in BSD. A typical Linux distribution includes: The Linux kernel, some GNU libraries and tools, a command-line shell, an X Window System for graphical interfaces, and a corresponding desktop environment, such as KDE or GNOME, and contains thousands of types of office suites, compilers, Text editor to the application software of scientific tools.

Because of the growing number of Linux companies, such as the famous red Hat, OpenLinux, Mandrake, Debian, SuSE and so on. So a lot of people are worried, so is every distribution (installation kit) different? This does not need to worry, because each distribution is architecture in the Linux kernel down the development of their own company style distribution, so everyone adhere to the Linux standard Base (LSB specification, that is, Each distribution in fact is similar, the use of all is the Linux Kernel, but each distribution inside the use of each package may not be identical only).

The development of Linux