At present, our common operating system has:1> desktop operating system
- Windows Series
- MacOS
- Linux
- Less application software
2> Server operating system
- Linux
- Safe, stable, free
- High Share
- Windows Server
3> Embedded Operating system
4> Mobile Device Operating system
- Ios
- Android (based on
Linux )
The development history of Linux operating system 1.1 Unix
Before 1965, the computer was not as common as it is now, and it was not something that the average person could touch, unless it was a military or college research institution, and the mainframe was able to provide up to 30 terminals (30 keyboards, monitors) to connect a computer
In order to solve the problem of insufficient quantity
- After the left of 1965, Bell Labs joined the Massachusetts Institute of Engineering and GE co-operation program to build a multi-user (multi-user), multitasking (multi-processor), multi-layered (multi-level) MULTICS operating system To enable large hosts to support 300 terminals
- The project was slow and funding was scarce around 1969, and Bell Labs withdrew from the study
- Ken Thompson, who withdrew from the project in 1969, was bored in the lab to allow a free computer to run the "Space Travel" parade, with a 1-month period of time for his wife's visiting relatives around August, using a compilation to write out Unix The prototype of the operating system
- Ken Thompson of the Bell Lab in 1970, based on the BCPL language, designed a very simple and hardware-like B language (taking BCPL's initials), and he wrote the first UNIX operating system in B language.
- In 1971, Dennis M.ritchie, who was also fond of "Space travel", was able to play games earlier, joined Thompson's development project, collaborated on UNIX, and his main job was to transform the B language because of the poor cross-platform of B language.
- In 1972, Dennis M.ritchie finally devised a new language based on the B language, and he took the second letter of Bcpl as the name of the language, which is the C language
- At the beginning of 1973, the main body of the C language was completed, and Thompson and Ritchie eagerly began using it to completely rewrite the now-famous Unix operating system
1.2 Minix
- Because of changes in GE's policy, after Version 7 Unix was launched, new terms of use were released, the UNIX source code was privatized, and Unix source code could no longer be used in universities
- Andrew S. Tanenbaum (Baum) professor, in order to be able to teach the details of the operation of the student operating system in class, decided to develop a UNIX-compatible operating system without using any of the source code, in order to avoid copyright controversy
- In the sense of small UNIX (Mini-unix), it is called MINIX
1.3 Linux
- 1991 Linus (Linus) had a strong interest in Unix during his studies at the University of Helsinki, trying to do some development work on Minix.
- Because Minix is only used for teaching, so the function is not strong, Linus often use his terminal emulator (Terminal Emulator) to access newsgroups and Mail on the university host, in order to facilitate reading and writing and download files, he wrote the disk driver and file system, which later became The first prototype of the Linux kernel, when he was only 21 years old!
- Linus uses GNU's bash as the development environment, GCC as a compilation tool, wrote the Linux kernel, at first 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
- Linux is only available at the beginning of the 386, and later through the world's friends to help, eventually compatible with a variety of hardware
Assembly
C language
- When using UNIX to migrate to other types of computers, the powerful portability of C (portability) appears here
- Machine language and assembly languages are not portable, the program developed for x86, it is impossible to run on machines such as Alpha,sparc and ARM.
- The C language program can be used on any architecture of the processor, as long as the processor of that architecture has the corresponding C language compiler and library, and then the C source code compiled, connected to the target binary files can be run
Unix genealogy
Linux kernel and release version 2.1 Linux kernel version
- The kernel (kernel) is the heart of the system, the core program that runs programs and manages hardware devices like disks and printers, and it provides an abstraction layer between bare devices and applications
- Linux kernel version is also divided into stable version and development version, the two versions are interrelated, mutual circulation
- Stable version: Industrial-grade strength, can be widely used and deployed. The new stable version is relative to the older just fix some bugs or add some new drivers
- Development version: Due to the testing of various solutions, so changes quickly
- Kernel Source URL: http://www.kernel.org
All changes to the Linux source code from all over the world will eventually be aggregated to this site, which is screened and modified by the open source community led by Linus and ultimately decides whether to enter the Linux mainline kernel source
2.2 Linux Distributions
On almost every list of Linux-related lists, Debian-based Ubuntu occupies one seat. Canonical's Ubuntu is better than all other Linux server distributions-from simple installation, excellent hardware discovery, to world-class business support, Ubuntu sets tough standards that are hard to match
application area of Linux 3.1 server domain
- The application of Linux in server domain is its important branch
- Linux free, stable, efficient and other features here has been very good embodiment
- Early due to maintenance, operation and other reasons are also subject to great restrictions
- In recent years, the Linux server market has been rapidly improved, especially in some high-end areas especially
3.2 Embedded Field
- In recent years, the application of Linux in embedded field has been improved rapidly.
- Linux is stable, good support for the network, low cost, and can be tailored to the needs of the software, the kernel can be up to hundreds of KB minimum, so that its application in the embedded field in recent years has been greatly improved
Main applications: Set-top box, digital TV, VoIP, SPC, mobile phone, PDA, etc. are its application areas, has been Google, Samsung, Motorola, NEC and other companies to promote
3.3 Person Desktop Field
- This area is the weakest link in traditional Linux applications
- Traditional Linux has been suppressed by Windows because of its simple interface, complicated operation and less application software.
- In recent years, with the emergence of excellent desktop environments such as Ubuntu and Fedora, and the increasing support of major hardware vendors, Linux has gradually increased in the field of personal desktops.
Common operating systems and Linux history
