"What Linux is" Linux is what Linux Unix's history

What is Linux

The same set of operating systems cannot be run on a platform of different architectures.
Refer to the HARDWARE function function and modify your operating system program code, the revised operating system will be able to run on another hardware platform. This is the software migration .
Linux is an open-source operating system, so its program code can be adapted to run on a variety of machines. Linux is portable .

Linux provides a complete architecture of the lowest level of hardware control and resource management in the operating system, which is consistent with the good tradition of Unix, so it is fairly stable and powerful.

Linux before the History of Unix 1969 ago: A great dream--bell MIT with GE's "Multics" system

The early 1960s MIT developed a time -sharing operating system (Compatible time-sharing system CTSS)
It allows large hosts to connect to the host by providing multiple terminals, thereby leveraging the host's resources for computing. at this point the terminal only the input and output function, itself completely does not have any operation or software installation capabilities. And can only provide up to 30 terminals.

Around 1965, the Multics project was launched by Bell's Massachusetts Institute of Science ( MIT) and General Electric (GE) , which aims to enable large hosts to deliver more than 300 terminals simultaneously. the target used by the connection.
Finally multics difficult to complete but not much attention. But the talent of Multics project training is very good.

1969: Ken Thompson's small file Server System

After exiting from Multics, Ken Thompson struggled for 4 weeks, writing out a set of kernel programs in assembly language, including some kernel utilities and a small file system. This is the prototype of UNIX. (UNICs)
The File Server system has two important concepts:
① All programs or system devices are files.
② Regardless of whether the build editor or the subordinate file, the program written only one purpose is to effectively accomplish the goal.
These concepts later have a significant impact on the development of Linux.

1973: Unix officially born, Ritchie and others write the first official UNIX kernel in C language

In 1973, Thompson and Ritchie collaborated with the C language to rewrite and compile the UNICs kernel, and finally released the official version of UNIX. The change is also UNIX that can easily be ported to different machines.

1977: Important Unix Branch--bsd born

UNIX is written in the C language and is theoretically portable. As long as the UNIX source code, and for the characteristics of large host to revise the original source code, it is possible to migrate UNIX to another different host. So , 1973 years later, UNIX was developed in collaboration with the University of California, Berkeley.
Increase Bill Joy in the process of porting UNIX to add a lot of tool software and compiler program, and finally named it Berkeley software distribution (BSD). BSD is a very important branch of UNIX.
Bill Joy is also the founder of Sun's company. Sun is developing its own commercial UNIX version of the BSD-developed kernel. (later can be installed in the x86 hardware architecture above FreeBSD is the BSD revision come!) )

1979: Important System V architecture and copyright notice

because of the highly portable and powerful performance of UNIX, and the fact that there was no copyright dispute at the time, many commercial companies began to develop the UNIX operating system.
The kernel of the operating system must be in line with the hardware to provide and control hardware resources for good work. In the early days, every company that produced computer hardware had no concept of agreement, so the hardware produced by each computer company was naturally different. In addition, since no vendor has designed UNIX systems for personal computers (the CPU in the early PC architecture is not capable of multitasking), the previous UNIX can only be equated with servers or large workstations .

In 1979, at/T introduced System V version seventh UNIX, which supported the x86 architecture of the personal computer system.
AT/t for business reasons, want to take the copyright of Unix back. Therefore, the seventh edition of System V specifically mentions "cannot provide the source code for students".

What is now known as purebred Unix refers to the System V and BSD two sets.

1984: x86 architecture Minix operating system was born

University professor Andrew Tanenbaum wrote Minix the Unixlike kernel program. To avoid copyright issues, he never looked at System V's source code during the writing process.
Minix also opened the source of the original stacking on disk for sale on the precedent.
Because Minix is thought to be used in education, the professor is donuts to Minix.

1984 bis: The GNU Project and the FSF Foundation

Richard Mathew Stallman grew up in a sharing-focused hacker circle. Starting with UNIX development, in order to allow the software to run on different platforms, Stallman the software he developed into a portable type, that is, he will publish the program's source code.

in 1984, Stallman began the GNU project. The purpose of this project is to create a free and open Unix operating system.
Later Stallman now writes small programs on UNIX, gradually widening the popularity of the GNU project. But Stallman really created the original idea of operating the OS until the advent of Linux.
Later, the GNU project began to compile the C language compiler, the famous GNU C Compiler (GCC) ( notable GNU project and program editor Emacs , etc.)
Then Emacs earned a sum of money, Stallman set up the Free Software Foundation (Software Foundation, FSF), inviting more engineers and volunteers to write software.

General Public License for GNU

To avoid the GNU project's free software being exploited by others as a proprietary software, a well-known common Public License (License GPL) was drafted and called it CopyLeft ( Relative to the copyright of the patented software)
Several important software developed by GNU: Emacs GNU C (GCC) GNU C Library (GLIBC) Bash Shell

1988: Graphical Interface XFree86 Project

In 1984, the X Window System was first published by MIT and other third parties and a non-profit XFREE86 (X Window System + Free + x86) was established in 1988.
The GUI interface of XFREE86 was integrated into the Linux operating system when Linux kernel version 1.0 was released in 1994.

1991: A message from Finnish university student Linus Torvalds

1991 Torvalds on the University BBS began the extraordinary journey of Linux.

About the GNU Project free Software activities

The act of releasing the source code together with the software is free software movement.

Copyright of free software GNU GPL

In order to avoid the development of their own open source free software was taken to make commercial software, indicating that Stallman also the GNU and the FSF developed software is linked to the GPL's copyright notice. The core concept of the FSF is that the Copyright system is a means to promote social progress, and copyright itself is not a natural power.

The true meaning of freedom (free)

Free: The focus is not on freeware, but on the user's freedom to perform a copy-and-release study to modify and enhance free software.

Free software and business conduct

Free software can be sold in the form of a service.

"What Linux is" Linux is what Linux Unix's history