UNIX is the old operating system that is still alive. It has gone through the course of 40 years (see "UNIX 40 years: Unix yearbook", "UNIX 40 years: yesterday, today and Tomorrow). In today's rapidly updated computer world, Unix has always maintained its holy aura, its twists and turns, its sighing history, and the ideological changes it has triggered, the profound impact on today's computer culture, the people and things that have taken place over the past 40 years, have turned it into a legend that cannot be left alone.
This is a history that all people in the computer industry, especially software developers, need to understand. The legendary history of UNIX is the most representative of the whole computer world culture. It has the greatest and most profound influence on the whole computer world culture. His experience in the past has brought us a new trend of thought in the computer world.
Only by understanding the history of this period can we understand the right, the right, and the right, the right, and the right. Hope that this article will allow you to feel the powerful pulse of the computer world, so that you can embark on this exciting road.
Part 1
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UNIX Origin
Looking back at the history of UNIX, we need to talk about a project called multiplexed information and computing service. In the 1960s s, most computers used batch processing (that is, when a job accumulates a certain number of jobs ). At that time, our well-known American Telephone and Telegraph Inc .; at&t, General Electric Appliance Company (General Electric ICS; G. E .) and mas usetts Institute of Technology (MIT) are planning to develop a general-purpose, time-sharing, and multi-user operating system, this multics was designed to run on a large GE-645 host. However, this project is too complex, the overall goal is too large, it combines too many features, the progress is too slow, there has been no results in a few years, and the performance is very low. So in February 1969, Bell Labs decided to withdraw from the project.
Anyone familiar with this history knows that there is a Ken Thompson in Bell's lab who writes a game called space travel for the multics operating system, after running on multics, he found that the game was slow and expensive-$75 for each operation. After exiting the project. To make the game play, he found Dennis Ritchie to develop an extremely simple operating system for the game. This is the later UNIX. (It is worth mentioning that at that time they wanted to write in DEC-10, and later did not apply, I had to find a abandoned digital PDP-7 mini computer at the corner of the lab to make their plan, and the computer didn't even have an operating system, so they developed an operating system prototype in just a month using the assembly language.) their colleague Brian kernighan liked the system very much and laughed at Ken Thompson: "The system you wrote is really bad. It's just called UNICs." The name of UNICs is a nickname relative to multics. The post industry is changed to Unix. As a result, Unix was created by games and jokes. It was in August 1969. This year, Linus Torvalds, the father of Linux, was born in Finland.
In 1971, Ken Thompson wrote a sufficiently long application report and applied for a PDP-11/24 machine. So the first version of UNIX came out. Finished on a PDP-11/24 machine. This computer only has 24 KB of physical memory and KB of disk space. UNIX occupies 12 kb of memory, and the remaining half of memory can support space travel games for dual-purpose users. The well-known fork () System Call emerged at this moment.
In 1973, Ken Thompson and Dennis Ritchie felt that it was too headache to use the assembly language for transplantation. They wanted to use the advanced language to complete the third version.ProgramTheir ideas are crazy. At first they tried to use Fortran, but they failed. Later, they developed it in a language called BCPL (Basic combined programming language). They integrated BCPL to form the B Language. Later, Dennis Ritchie thought that the B Language still could not meet the requirements, that is, the Language B is improved. This is the famous C language today. Therefore, Ken Thompson and Dennis Ritchie successfully used the C language to rewrite the third-edition Unix kernel. So far, the UNIX operating system is quite convenient to modify and transplant, laying a solid foundation for the popularization of UNIX in the future. While the perfect combination of UNIX and C becomes a unity, C and Unix soon become the world's dominant.
The first UNIX article "the Unix Time Sharing System" consists of Ken Thompson and Dennis
Ritchie was published on the communications of the ACM in July 1974. This is the first time Unix has been exposed to the outside world. As a result, it has aroused widespread interest in the academic community and obtained the source code. Therefore, the fifth version of UNIX provides the Protocol "for educational purposes only" to various universities for teaching, became an example textbook in the operating system course at that time. Various University companies began to improve and expand UNIX through the Unix source code. As a result, UNIX is widely used.
Ken Thompson & Dennis Ritchie
UNIX splitting
In 1978, it was a revolutionary year for UNIX, because the academic leader UC Berkeley launched a sixth version, added some improvements and new features into UNIX. This is the famous "1 BSD (1st Berkeley Software Distribution)", which created another branch of UNIX: BSD series. In the same period, at&t established the USG (UNIX Support Group) to convert UNIX into commercial products. Since then, bsd unix and at&t's Unix stand-alone courtesy. UNIX is divided into the system IV and 4.x BSD mainstream, each of which is booming.
The seventh version of UNIX, published in 1979, is called "the last real Unix". The Unix kernel of this version is only 40 K bytes. Later, this version was transplanted to the VAX machine (I used this VAX machine when I was studying C language in College). I still remember that my biggest hobby on the VAX machine was to use the talk command to chat with others, haha ). Versions 8, 9, and 10 released in 1980s are only authorized to a few universities.
In 1982, at&t developed the first version of UNIX system III based on version 7, a commercial version for sale only. To solve the chaotic unix version, at&t integrated various Unix developed by other universities and companies and developed UNIX System V Release 1. This new commercial UNIX version is no longer includedSource codeTherefore, the University of California's Berkeley continued to develop bsd unix as an alternative to Unix system III and V. One of the most important contributions of BSD to Unix is TCP/IP. BSD has eight major releases including TCP/IP: 4.1c, 4.2, 4.3, 4.3-tahoe, 4.3-reno, net2, 4.4, and 4.4-lite. TCP/IP in these releasesCodeAlmost all of the current TCP/IP implementations of the system's predecessors, including at&t System v unix and Microsoft Windows TCP/IP are referred to the BSD source code.
At the same time, some other companies have begun to provide commercial Unix systems for their minicomputers or workstations, some choose System V as the basic version, and some choose BSD. Bill Joy, a major developer of BSD, developed SunOS Based on BSD and finally founded Sun Microsystems.
Bill Joy
In 1991, a group of BSD developers (Donn Seeley, Mike Karels, Bill jolitz, and Trent Hein) left the University of California and founded Berkeley Software Design, Inc (bsdi ). Bsdi is the first vendor to provide full-featured commercial bsd unix on cheap and common intel platforms. Later, Bill jolitz left bsdi and started the ipvbsd job. Javasbsd is considered FreeBSD, OpenBSD and NetBSD, dragonflybsd.
This is a UNIX era in which at&t wants to privatize itself. To privatize UNIX, in 1986 IEEE appointed a commission to develop a standard for one open operating system, known as POSIX (Portable Operating Systems Interface ). Add X to the end. I don't know whether it is for good or because it is essentially a UNIX standard. Of course, at&t UNIX won the standard-setting war and the registered trademark UNIX. At this time, the advocates of BSD are the opposite of the cold and heartless corporate empire. In terms of sales volume, at&t UNIX never keeps up with BSD/Sun. By 1990, at&t and BSD had been difficult to distinguish, because each of them had their own new inventions.
During this period, Unix shared by the world from the laboratory was in a critical period of privatization. (Here is a joke: Alice in UNIX Wonderland.)
UNIX legal disputes
Berkeley Software Design, Inc (bsdi) soon had a legal dispute with at&t's Unix systems laboratories (USL) subsidiary, which is registered by at&t. At&t filed a lawsuit against bsdi in 1992 to protect UNIX against System V copyrights and Unix trademarks, saying BSD had plagiarized his source code. Finally, the BSD system was well received.
As the final decision is pending, this legal lawsuit will delay the development of the descendant of BSD, especially the Free Software, for two years, which leads to great support for the Linux kernel without legal issues. Linux and ipvbsd started almost simultaneously. Linus said that if there was a free 386-based UNIX-like operating system, he might not create Linux. Although it cannot predict the impact on the software industry in the future (without this legal dispute, it is likely that today's revolutionary Linux will not exist), it is certain that, linux has enriched this field.
This lawsuit keeps hitting at&t to sell its UNIX system laboratory. The new Novell company has adopted a more open-minded approach to allow bsdi to freely release its own BSD, however, the premise is that the code from at&t must be completely deleted, so the 4.4 BSD Lite version was born. Because this version does not have legal issues, 4.4bsd lite became the basic version of the modern BSD system.
This lawsuit was finally concluded in January 1994, more satisfying the interests of bsdi. Of the 18,000 files in Berkeley kit, only 3 files need to be deleted, and 70 other files need to be modified, and the USL copyright description is displayed. This mediation also requires that usl not file a lawsuit against 4.4bsd, whether it is a user or a distributor of bsdi code. As a result, bsd unix has taken the road to restoration. BSD development has also taken several different directions and eventually led to the emergence of FreeBSD, OpenBSD, and NetBSD.
Since at&t realized the commercial value of UNIX and no longer authorized the Unix source code to academic institutions, Unix has been changing and its copyright owners have been changing for decades to come, the number of authorizations is also increasing. UNIX copyrights were once owned by at&t, and then Novell owns UNIX, and then Novell sold the copyrights to SCO (this fact remains controversial ). Many large companies developed their own UNIX products after obtaining UNIX authorization. (A few years ago, Microsoft was rumored to have asked SCO to court Linux to plagiarize its source code to restrict Linux)
Since UNIX is written in C language, modification and transplantation are very easy. Therefore, many commercial companies and academic institutions have joined the development of this operating system, different Versions of UNIX have also begun to flourish. This has produced so many UNIX derivatives today. Such as Aix, Solaris, HP-UX, Irix, OSF, and Ultrix. (These commercial Unix basically come from at&t-authorized UNIX System V)
UNIX open-source organizationAt&t's business attitude made many UNIX lovers and software developers feel quite sad and worried at the time. They believed that the restrictions on commercialization were not conducive to the development, on the contrary, many problems still occur in the products. With the various restrictions and problems of commercialized UNIX versions, public dissatisfaction and opposition have been aroused. As a result, Everyone began to form a "Rebel Alliance" in an organized manner to combat the commercial activities such as at&t in the cities where the customer was forced to stop.
On the other hand, "Cathedral" (centralized, closed, controlled, and confidential) and "market" (decentralized, open, and precisely reviewed by colleagues) the comparison between the two development modes has become the central idea of the new trend of thought. This new trend of thought has had a profound impact on the IT industry. It has brought revolutionary values to the entire computer world.
At this time, a leader named Richard Stallman appeared. He thought Unix was a very good operating system. If everyone could contribute what they learned, the system would be even better! The concept of open source he advocated is to oppose the commercialization and privatization of products in the laboratory in the case of UNIX. Although Stallman is neither a Unix programmer nor a Unix programmer, in the later 1980 environment, achieving a Unix-like operating system has become his clear strategic goal. Most of Richard Stallman's early donors were veteran ARPANET hackers new to Unix land. They had a sense of mission to share code, even stronger than those with more UNIX backgrounds.
For this ideal, Richard Stallman started GNU in 1984 and planned to develop a set of software compatible with Unix. In 1985, Richard Stallman created the Free Software Foundation to provide technical, legal, and financial support for the GNU program. Although the GNU program is mostly made by individuals voluntarily and without compensation, FSF sometimes employs programmers to help write programs. When the GNU program began to succeed, some commercial companies began to intervene in development and technical support. The most famous one is Cygnus solutions that were subsequently merged by red hat.
The establishment of the GNU Organization continued the first appearance of UNIX in that year and provided reliable legal and financial support for this situation. Over the past decade, the GNU project has become a major force influencing software development and has created countless important tools. For example, a strong compiler, a powerful text editor, or even a full-featured operating system. Since then, many programmers have gathered to develop a free, high-quality, easy-to-understand software that enables UnixCommunityVibrant and prosperous.
Since the launch of this program in 1990s, GNU has begun to generate or collect a large number of necessary components of various systems, such as libraries, compilers, and debugging tools) text editors, Web server, and a Unix User Interface (Unix shell. However, for various reasons, GNU has never developed an operating system's kernel. While Richard Stallman was worried about the operating system kernel, Linux appeared.
Linux was born
In 1990, Linus Torvalds was a student at the University of Helsinki, Finland. He initially wrote a program in assembly language to handle multi-task switching in 80386 protection mode, later, I was inspired by minix (a very small UNIX operating system written by Professor Andy Tanenbaum, mainly used for operating system teaching, the idea of self-arrogance was further developed-to write a minix better than minix, so I began to write some hardware device drivers, a small file system. In this way, the 0.0.1 version of Linux will come out, but it only has a tough prototype of the operating system kernel and cannot even run. You must compile it on a minix machine before you can play it. At this time, Linus was completely fascinated and didn't want to stop. It decided to kick off Minix. So Linux 0.0.2 was released in October 5, 1991 and bash and GCC can be run in this version.
From the very beginning, Linus decided to spread Linux freely, including the original code. Then Linux caught hacker's attention and added Linux kernel development through the computer network. Linux tends to be a hacker's system-until today, kernel development in the Linux community is considered real programming. Thanks to the addition of a group of high-level hackers, Linux has developed rapidly. A new version or a modified version has appeared in almost a week or two. By the end of 1.0 at the beginning of, Linux was finally born! Linux 1.0 is already a fully functional operating system, and the kernel is compact and efficient. It can make full use of the hardware performance and perform very well on 80386 machines with 4 MB of memory, people are still talking about it. To date, the kernel version has been released to 2.6. The development of Linux is not like traditional software engineering. It is a set of operating systems composed of masters from all over the world through the network. Here we can also see the power of fast network communication. For the first time, Linux made the world feel the power of open source and network. (The logo and mascot of Linux are a penguin named tux because Linus was bitten by a penguin in a zoo in Australia, the penguin is selected as the logo of Linux .)
Linux history is closely related to GNU. The GNU program, which began in 1983, is committed to developing a free and complete Unix-like operating system, including software development tools and various applications. By the time the Linux kernel was released in 1991, GNU had almost completed the development of various necessary software except the system kernel. With the efforts of Linus Torvalds and other developers, the GNU component can run on the Linux kernel. The entire kernel is based on the GNU General Public License, that is, the GPL (GNU General Public License, GNU General Public License), but the Linux kernel is not part of the GNU program. In March 1994, The linux1.0 version was officially released. Marc Ewing established the Red Hat Software Company and became one of the most famous Linux distributors.
Strictly speaking, the term Linux only represents the Linux kernel, but in fact people are used to using Linux to describe the entire Linux kernel, and the operating system (also known as GNU/Linux) that uses various tools and applications of the GNU project ). Linux software based on these components is called the Linux release version. Generally, a Linux release kit contains a large number of software, such as software development tools, databases, web servers (such as APACHE), X Windows, and desktop environments (such as gnome and KDE ), office kits (such as OpenOffice.org.
From 1991 to 1995, Linux evolved from a conceptual 0.1 kernel prototype to an operating system comparable to proprietary UNIX in terms of performance and features, in addition, the vast majority of these UNIX types were defeated in important statistics such as continuous normal working hours. In 1995, Linux found its killer application, Apache, an open-source Web server. Like Linux, Apache is extremely stable and efficient. Soon, the Linux machine running Apache became the first choice for the global ISP platform. About 60% of websites use Apache, which easily beat the other two major proprietary competitors. Today's lamp (Linux, Apache, MySQL, PHP) has become the primary choice for architecture Web servers.
Nowadays, Linux not only can be installed on almost all mainstream servers, but also desktop x86 systems. It is also often used in embedded systems, set-top boxes, mobile phones, switches, game consoles, PDAs, network switches, routers, and so on, because of the wonderful Linux kernel.
The emergence of Linux not only brings a free operating system to the world, but also a continuation of the culture of freedom and sharing of UNIX, its emergence has brought more mature ideas and cultures in the computer world since UNIX and GNU.
Linux leader today
The relationship between Linux and GNU is quite subtle. At that time, the user software toolkit compiled by the Free Software Foundation paved the way forward for getting rid of high-cost proprietary software development tools. Consciousness obeys the economy, not leadership: some new users have joined the RMS Revolutionary Movement, held high the GPL flag, while others have agreed with the UNIX tradition in the overall sense and joined the camp against GPL, however, most other people are dedicated to coding.
Linus Torvalds cleverly crossed the GPL and anti-GPL factions. He used the GNU toolkit to build his own Linux kernel and protected it with GPL's infectious nature, but refused to agree with the thought system plan reflected by Richard Stallman's license agreement. Linus Torvalds makes it clear that he thinks free software is generally better, but he occasionally uses proprietary software. Even in his own career, he refused to become fanatics. This has greatly attracted the majority of hackers. Although they have long been disgusted with Richard Stallman's words, their suspicion has been lacking an influential or convincing spokesperson. Linus Torvalds exactly plays this role.
Linus Torvalds's pleasant pragmatism and flexible and low-key style have prompted the hacker culture to win a series of amazing victories between 1993 and 1997, not just technological success, it also gave a solid start to the release, service, and support industries of Linux operating systems. As a result, his fame and influence are also soaring. Torvalds became a hero in the Internet age. By 1995, he had been famous in the hacker culture for only four years, and Richard Stallman spent 15 years on it, in addition, he far exceeded the history of Stallman selling "Free Software" to the outside world. Compared with Torvalds, Richard Stallman's words gradually become harsh and powerless. (See "Top 10 Linus Torvalds quotations")
Today, we cannot tell whether it is GNU Linux or Linux GNU. Linux neither supports open source nor commercialization. Linus believes that good software needs to be promoted together for free and commercialization. It is this revolutionary idea that has created today's popular Linux environment (see "who wrote Linux", "Linux Foundation advertisement", and "Linux distribution timeline"). Linux is like a clear spring flowing into everyone's hearts, which has aroused a lot of inspiration and thinking.
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