Get to know Linux
1.What is an operating system< /p>
Operating System (Operating System, referred to as OS) is a computer program that manages and controls computer hardware and software resources. It is the most basic system software that runs directly on the “bare metal”. Any other software must be operating Can only run under the support of the system.
2.The operating system in real life
win7
Mac
< p>
< p>Android
iOS
3. The history of the development of operating systems< /strong>
Unix
Before 1965, computers were not as common as they are now. It is not something that ordinary people can touch, unless It is a military or academy research institution, and the mainframe at that time can provide at most 30 terminals (30 keyboards, monitors), and connect to a computer
In order to solve the problem of insufficient quantity
In 1965, the left and the back of the shell Bell Labs, Massachusetts Institute of Technology, and General Electric jointly initiated the Multics project. They wanted the mainframe to support 300 terminals.
Before and after 1969, the progress of the project was slow and funds were short. Bell Labs withdrew from the research< /p>
Ken Thompson, who withdrew from this project in 1969, was bored in the laboratory. In order to run the “Interstellar Travel” parade on an idle computer, he took advantage of his wife’s time to visit relatives around August. , It took 1 month to write a prototype of the Unix operating system
In 1970, Ken Thompson of Bell Labs, based on the BCPL language, designed a very simple and close to the hardware B Language (take the first letter of BCPL), and he wrote the first UNIX operating system in B language.
Because of the poor cross-platform nature of the B language, in order to be able to run this great Unix operating system on other computers, Dennis Ritchie and Ken Thompson are preparing to study a better version based on the B language. Good language
Ken Thompson (left) and Dennis Ritchie (right)
In 1972, Dennis Ritchie of Bell Laboratories, USA, finally based on the B language Designed a new language. He took the second letter of BCPL as the name of the language. This is the C language.
In early 1973, the main body of the C language was completed. Thompson and Ritchie can’t wait to use it to completely rewrite the now famous Unix operating system
Minix
Because of AT&T (General Electric) policy changes, After the release of Version 7 Unix, new terms of use were issued to privatize the UNIX source code, and the UNIX source code can no longer be used in universities. In order to teach students the practical details of operating system operation in class, Professor Andrew S. Tanenbaum decided to develop a UNIX-compatible operating system without using any AT&T source code to avoid copyrights. Controversy. He called it MINIX with the meaning of mini-UNIX.
Linux
Because Minix is only used for teaching purposes, its functions are not strong, so Torvalds uses GNU bash as a development environment and gcc as a compilation tool for writing Linux kernel-v0.02 is removed, but at the beginning Linux is not compatible with Unix, that is, applications running on Unix cannot run on Linux, that is, the interface between the application and the kernel is inconsistent, because Unix follows the POSIX specification, so Torvalds modified Linux and followed POSIX (Portable Operating System Interface, which standardized the interface specifications between applications and the kernel); at first, Linux was only applicable to 386, and later with the help of netizens all over the world, it was finally compatible with a variety of hardware;
Linus Torvalds
Development of operating systems
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