Linux Learning Notes (1) ~linux Interesting historical overview

Dedicated to knowing Mono, knowing Jexus, and interested in. NET mashup technology.

In 1965, Bell, MIT and GE launched the Multics program, with the goal of implementing an operating system that allows large hosts to connect to 300 endpoints. (The time-sharing operating system is not as now ... )

In 1969, the Multics program lagged behind, funding was scarce, and Bell Labs withdrew from the plan, but the people who had been involved in the Multics program got some inspiration. Ken Thompson is one of them.

Ken Thompson is said to be trying to develop a set of operating systems to meet his needs in order to transplant a "space travel" game. After four weeks of struggle (this guy is simply not human.) ), he finally wrote a set of core programs in assembly language (assembler), including some core tools and a small file system. That system is the prototype of Unix! At that time Thompson would Multics a large and complex system to simplify a lot of, so with the lab friends are nicknamed this system: UNICs.

Because the operating system that Thompson wrote was so good, it was widely circulated inside Bell Labs, and it was revised several on a few occasions. Later, Thompson worked with Ritchie to change UNICs to higher-order programming languages. The ready-made high-level programming language had a B language. But the core function compiled by the B language is not very effective. Later Dennis Ritchie the B language into C (in other words C was developed at this time), then rewritten and compiled the core of the UNICs in C, and finally released the official version of UNIX. (This group of high-level hackers ...) )

Because Bell Labs is affiliated to the two American telecom manufacturers at the company, but at the time of the busy other business activities, UNIX does not support or exclusion. In addition, UNIX was developed at this time by the engineers at Bell Labs, a group of engineers who were quite interested in the program, but Unix was not generally acceptable at the time. But for academics, UNIX is the gospel for academics to study because the code can be rewritten and used for academic research.

1977, an important version of Unix, BSD was born.

In 1979, at/T, because of considerations in business and in the real world at that time, he wanted to reclaim the copyright of Unix. Therefore, at/T in the Seventh edition of Unix issued in 1979, special reference was made to the strict restrictions on the provision of source code to students. At the same time, it also caused the tension between the Unix industry, and also detonated a lot of business disputes ~

This is the most uncomfortable, who is it? Professor. Think, if there is no core source code, how to teach students to know Unix? This is a very hurtful question for Professor Andrew Tanenbaum (Tan Ningbong). However, the school curriculum has to continue, then what? Professor Tan Ningbong himself wrote Minix this Unix like core program! In the process of writing, in order to avoid copyright disputes, Tan Ningbong completely do not look at the Unix core source code! (It deserves to be a professor ...) and emphasize that his Inix must be compatible with Unix! Tan Ningbong began writing the core program in 1984 and was finally completed by 1986. Called Minix (meaning: Mini Unix)

Minux operating system developers only have Tan Ningbong professor, because the scholar is very busy Ah! Plus Tan Ningbong always think Minix is mainly used for educational purposes above, so for Minix is donuts! Yes, Minix is very popular, however, the voice of the user's requirements/needs may not be able to rise to a higher place!

This time is not Linux on the show, not yet, introduce another story line.

When Professor Tan Ningbong wrote Minix, there was another thing to do at the same time. That's the GNU program. The GNU program was launched by Richard Mathew Stallman (Storman), a program that has an indelible effect on today's free software craze.

Richard Mathew Stallman (born 1953) was very smart from a young age. When he was in 1971, he went to the very famous AI lab in the hacker Circle, where the hacker circle focused almost all of the software on "sharing", so there was no patent problem, which had a big impact on Storman, but later, because of management issues, Leading the lab's best hackers to leave the lab and enter other commercial companies to continue to develop excellent software. Storman, however, continued to develop new programs and software in the original laboratory. Later, he found himself unable to complete all the work, so he wanted to set up an open team to continue his efforts.

After 1983, because of the replacement of the laboratory hardware, so that Storman can not continue to the original hardware and operating system to continue to write the free program ~ and he further found that in the past, he used the Lisp operating system, is the MIT patent software, is not shared, This is a hindrance to the desire to set up an open community of Storman. Second, he gave up the Lisp system. Later, he came into contact with the Unix system and found that UNIX could be ported between different machines theoretically and practically. Although UNIX is still a proprietary software, at least UNIX architecture is still relatively open! So he started using Unix systems instead.

In 1984, Storman began the GNU program, which was designed to create a free, open UNIX operating system. But it's not easy to build an operating system! And at that time, the GNU is only a single person to fight the Storman ~ This is too much trouble, but do not want to give up the plan, what can be done?

The clever Storman simply counter his way and line ~ "Since the operating system is too complex, I will first write a small program that can run on Unix, this is always OK?" "In this idea, Storman began to refer to the existing software on Unix, shipowner based on the role of these software developed the same functions of software, during development Storman never look at the original code of other software, to avoid the lawsuit. Then a bunch of people know that the free GNU software, began to use the actual application of the original patent software compared to the difference is not too much, so instead of using the GNU software, the GNU program gradually open awareness.

Although the GNU program has gradually opened its profile, visibility is not enough. At this time Storman and thought: No matter what software, have to be compiled into a binary file (binary program) to be able to execute, if you can write a good compiler, that is the software we all need it? So he began to write the C program compiler, which is now quite famous GNU C Compiler (gcc)! (Linux's famous compiler surfaced!) In the process of writing, he established the Free Software Foundation (FSF, Software Foundation). In addition, he has written more C function libraries (GNU C library) that can be called, as well as basic interfaces that can be used to operate the operating system BASH shell!

It's all done in about 1990 years! (The famous bash shell on Linux surfaced again!) ）

By the year 1985, the free software developed by the License GNU was used by others to become a patented software, so he and his lawyer drafted a famous general Public License (the common common, the GPL) and called him copyleft (copy of the relative and benefit software). right! (Git knows the GPL, but I don't know how many people know about the history)

Since there are several important software developed by GNU (such as the Gcc,glibc,bash shell), many later software developers can develop programs with these basic tools! It is important to further expand the free software community. However, for GNU's original idea of "building a free Unix operating system", these excellent programs are still not satisfied, because there is no "free Unix core" present ... So the software is still only working on those patented Unix platforms ~ ~ Until the advent of Linux ...

In 1991, Linus Torvalds of the University of Helsinki in Finland posted a message on the BBS that he wrote a small core program with tools such as bash and GCC, a core program that works on Intel's 386 machines, which makes a lot of people interested! From now on, Linux is an extraordinary journey!

Linus Torvalds (Torvalds, born in 1969) was a statistician at the University of Helsinki, and his grandfather had brought him to his side to manage some micro-computers in order to get his grandson to learn something. In this period, Torvalds to the assembly language (Assembly Language), which is a direct and chip-to-talk programming languages, that is, the so-called low-level language. It is necessary to understand the architecture of the hardware, otherwise it is difficult to write programs in assembly language.

In 1988 years, Torvalds successfully entered the University of Helsinki, shipowner selected the Department of Computer Science. During his schooling, Torvalds was exposed to the Unix operating system because of his academic needs and interests. At the time, the entire Helsinki just had a new Unix system with only 16 terminals (terminal). Earlier computers had only a host computer, and terminal was only responsible for providing input/output. Under this kind of sentiment attaining, it is very difficult to satisfy the demand of the Watts, because ... Just waiting for UNIX is time-consuming-and he can't help but think: "Why don't I do a Unix game myself?" "But, like the GNU project of Stallman, it was hard to write the core program, but fortunately God did not deviate from Torvalds, because soon he knew there was a Unix-like system that was fully compatible with UNIX and could be in Intel 386 (the textbook I 386) machine running on the operating system, that is what we mentioned above, Professor Tan Ningbong for education needs to write the Minix system! (Really don't underestimate the professors ...) After buying the latest Intel 386 pc, he immediately installed the Minix operating system. In addition, Minix this operating system is attached to the original code, so Torvalds also through the source code to learn a lot of core program design concepts.

Torvalds in the process of studying Minix, found Minix although really great, but Tan Ningbong is not willing to carry out the function of the strengthening, resulting in a pile of engineers in the operating system function above the desire dissatisfaction! This time young Torvalds thought, "So, why don't I rewrite the os i want?" "The second is that he began the writing of the core program."

What does it take to compose a program? The first thing you need is the ability to work on the environment, and then you can compile the original code into an executable file compiled Asmeamerican sequence. Fortunately, with the GNU program provided by the Bash work environment software and the GCC compiler program and other free software, so that Torvalds can successfully write the core Asmeamerican sequence. Referring to Minix's design philosophy and the program code on the book, he then studied the performance optimization of the 386-person computer, then used the GNU free software to combine the core program code by not 386 tightly, eventually writing out the core program he needed. And this little thing really can be in the 386 above the smooth running up ~ can also read the Minix file system. Oh, that's great! But not enough, he hoped that the program can get some suggestions for changes, and the other is that he put the core in the Web to provide everyone to download, at the same time on the BBS posted a message: (This is the declaration of the advent of Linux)

Hello everybody out there using Minixi ' m doing a (free) operation system (just a Hobby,won ' t is big and professional like GNU) for 386 (486) at clones. I ' ve currently ported Bash (1.08) and GCC (1.40), and things seem to work. This implies that I'll get something practical within a few months, and I ' d like to know what features most people want. Any suggestions is welcome, but I won ' t promise I ' ll implement them:-)

He said he had completed a small operating system that was used on the 386 machine, and that he was really just having fun, not wanting to make a plan as big as GNU! In addition, he hopes to get more people to build acial and feedback to develop this operating system! This concept is just the opposite of Minix. The news attracted a lot of attention, and they also went to the website provided by the Watts to download the core to install. Interestingly, because the directory of the FTP site where Torvalds placed the core is Linux, so everyone calls this core Linux. (Linux at this time is just the kernel of Linux now)

Follow the story I will not say, Linux development to now, has been known

Linux Learning Notes (1) ~linux Interesting historical overview