"Introduction to Linux"

I. What is the operating system 1, definition

Operating system, English name operating system, abbreviated as OS, is essential in computer system software, it is the application operation and user operation necessary basic environmental support, is the core of the computer system.

2, the role of the operating system

• Manage and control hardware and software resources in computer systems, for example, it is responsible for directly managing the various hardware resources of a computer system, such as CPU, memory, disk, etc., while managing the priorities required for system resources.
• Control the input, output and operation network of the device and manage the file system and other transactions.
• The management of various kinds of software resources in computer system. such as the installation of various types of application software, set up the operating environment.

The operating system and computer hardware software diagram are as follows:

The operating system is the system program software that is used to transfer information between the user and the computer system hardware. For example, the operating system will pass the user input information to the computer system hardware core for processing, and then the computer system hardware processing results returned to the user.

Ii. what is Linux 1, Introduction and Features

Like the Windows operating system software, Linux is also an operating system software. At the beginning of the design, it was a computer based on the Intel x86 series CPU architecture. It is a POSIX-based multi-user, multitasking, multi-threaded and multi-CPU operating system.

The Linux operating system is so popular because it has the following features:

• Development of the source code of the program, can be freely modified.
• UNIX systems are compatible and have almost all of the best features of UNIX.
• Free to disseminate without any commercial copyright restrictions.
• A computer suitable for x86 CPU series architectures such as Intel.

2, the operating principle of Linux

• Linux is composed of a small program, a number of small programs together to complete a specific task
• Linux, all resources are files, including hardware devices
• In Linux, try not to capture the user interface. (As long as Linux can handle it, it will not request to the user, try not to occupy user resources)
• Linux, all configuration files are plain text files

3, the common Linux operating system

1. The Debiandebian is extremely stable to run, making it ideal for servers. But it is not suitable for novice users, but for system administrators and advanced users. Debian supports most of today's architectures (processors). 2. Gentoogentoo does not appear in precompiled form, but every time it needs to be compiled for each system. It is considered to be the best learning object and can then understand the internal workings of the Linux operating system. Gentoo's operating system is suitable for those users who are fully adept at Linux. 3.UbuntuUbuntu is a derivative version of Debian and is now the most popular free operating system. Ubuntu focuses on its application in this market, which is common in servers, cloud computing, and even some mobile devices that run Ubuntulinux. Ubuntu is an operating system that the novice user is sure to love. 4. Rhel This is the first Linux distribution for the commercial market. It has a server version that supports many processor architectures, including x86 and x86_64. 5.CentOSCentOS is an enterprise Linux distribution that is rebuilt with free source code from Red Hat Enterprise Linux. 6. Fedora's compact fedora is for those who want to try out the latest technology and wait for the stable version of the program. In fact, Fedora is a test platform for Red Hat, and the product is developed and tested on the platform before it becomes an enterprise-class release. 7.OpenSuseOpenSuse This Linux distribution is free and is not intended for commercial use and is still for personal use. It uses YaST to manage packages.

4, supplementary small knowledge points

program = data + instruction program must be loaded into the memory, must be run by the CPU time slice slice save the field to restore the field cache memory levels cache is to improve the speed of the data code is stored on the hard disk

Programming Languages Machine Language Binary assembly language (Microcode language) high-level language strong language (first compiled into binary code to execute): C + +, JAVA, C#,B,VC,VB (B Language for visual programming), VF weak language (side interpretation side Execution): Php,python, shelljavac,gcc

API application interface, integrated in the operating system kernel API is on different CPUs, using assembly language (high running efficiency) written by the same function of the program. The program itself does not run automatically, it just provides access to the application of the hardware interface can also say that the API to the program virtual the same type of execution environment.

System call systems invoke the operating system to provide users with user interface (special application) shell1. GUI (graphical user interface) Kde,cde2. CLI (Command line interface) BASH, csh,zsh

Library application repository Kernel library (kernel object). Ko shared library. Sodll (dynamic link library)

/dev/sda1sd-->serial disks serial disk a--> disk number sda1--> storage boot, boot partition, 100M, mount point:/bootsda2--> Swap partition (virtual memory) memory less than 256M, At least 256M swap partition; memory is greater than 256M, less than 2GB, swap partition size is twice times more memory than 2G, swap partition is not fixed mount: The process of associating a disk partition with a folder is called a mount point for the folder associated with the partition.

"Introduction to Linux"