Linux System Overview and installation

Computer basic knowledge modern computer hardware structure

Computer composition refers to the logical implementation of the system structure, including the data flow and control flow in the machine, the composition and logic design. Mainly divided into five parts: controller, arithmetic, memory, input device, output device

Software

Software is a general term for computer programs and related data relating to the operation of a data processing system.

• A program is a collection of instructions for a computer to complete a task
• Data is different types of information that are used or generated by the program

The basic composition of the Software:

1. The system software controls and manages the resources of computer systems, and provides services for users and other programs to operate.
2. Supporting software is software that assists software technicians in software development work.
3. Application software is a program designed to solve a certain type of application need or a specific problem.

Operating system

The operating system is the first layer of software on bare metal, which is especially closely related to hardware.

Definition: The operating system is a system software (or a collection of programs) that controls and manages various hardware and software resources within a computer system, effectively organizes multi-channel programs, and is the interface between the user and the computer.

• The operating system is software, and is the system software
• Its basic function is to control and manage various resources within the system and effectively organize the operation of multi-channel programs.
• It offers a wide range of services to facilitate user use and expand hardware capabilities.

Function:

1. Storage Management

⑴ Memory allocation

(2) Address mapping

(3) Memory protection

(4) Memory expansion

2. Process and Processor management

(1) Job and process scheduling

(2) Process Control

(3) Process communication

3. File Management

(1) Management of file storage space

(2) General management of file operations

(3) Directory Management

(4) file read-write management and access control

4. Device Management

(1) Buffer management

(2) Equipment allocation

(3) device driver

(4) Device independence

5. User interface

⑴ Graphical user interface (GUI)

⑵ Command Line interface

⑶ Program Interface--also called system call interface

system Calls

The system call is the interface between the operating system kernel and the user program and the application. On the Unix/linux system, the system call appears as a C function.

For example:

#include <sys/types.h><sys/stat.h><fcntl.h> ... fd=open ("file.c",  2);

The development of the operating system

1. Batch processing System

The system has two characteristics: one is "multi-channel", the second is "batch".

The main advantages are: ① system resource utilization is high, ② system throughput is large.

There are obvious shortcomings: ① user job waiting time, often go through a few 10 minutes, a few hours, or even a few days; ② no interaction ability, users can not interfere with their own operations, the use of inconvenient.

2, CTSS

In the time-sharing system, ticks are mainly referred to several concurrent programs to share the CPU times. It is implemented through the system software. Shared time units are called time slices.

The basic features of the time-sharing system can be summarized as four points:

• Simultaneous: A number of users can use computer system at the same time
• Interactivity: Users can easily engage in human-machine dialogue with the system
• Independence: Users in the system can operate independently from each other, interfering or destroying each other.
• Timeliness: Users can get a system response in a very short period of time

The main advantages are: To provide users with a friendly interface to facilitate the general application of the computer to facilitate the sharing of resources and exchange of information, for software development and engineering design provides a good environment. The main disadvantage is: Can not meet the real-time requirements, the system is larger, management is more complex.

3. Real-time system

Real-time system refers to the operating system with real-time characteristics, which can support real-time control system. This system is dedicated.

Three typical forms of application

1. Process Control systems.
2. Information Query System.
3. Transaction processing System.

4. Network operating system

In order to realize data communication and resource sharing between computers in different places, it is possible to interconnect multiple computer systems with geographically dispersed and autonomous functions to form a system, which is the computer network operating system.

Features of the network operating system:

1. Distribution of
2. Autonomous nature
3. Interconnection of
4. Visibility of

Linux

It can be divided into three modes according to the method provided and whether it is for profit, i.e. commercial software (commercial software), shareware (shareware) and free software (freeware or freeware software).
Linux is a free-to-release implementation version of a Unix-like kernel, which is the underlying core of an operating system

You can get the kernel source code, compile and install it, and then get and install many other free-release software to create a complete Linux, often called a Linux system.

Linux and Unix are very similar. Yes, Linux evolved on the basis of UNIX. That was Linus because of the contact with UNIX and then they want to develop a simple system kernel, he developed a simple system kernel is actually Linux. At that time Linus the development of the system kernel to the Internet to provide everyone download, because of its exquisite small, more and more enthusiasts to study it. People embellish the kernel and then become a system. Maybe you've heard of it, Linux is free. In fact, here's free only to say that the Linux kernel is free. On the basis of the Linux kernel, many versions of Linux have been generated.

Linux Status

• Kernel version number: Developed and maintained by Linus and other people, globally unified
• Release number: made by each issuing company or organization, there is no comparability between the release numbers of different companies
• Kernel version number format: X.y.z,x is the main version number, Y is the minor version number, and z is the revision number, for example: 4.4.16
• According to the nature of the user, the current Linux users can be divided into individual users, professional users and business users.

Some of the common Linux brands

• RedHat Linux
• SuSE Linux
• Mandrake Linux
• Caldera Linux
• Turbolinux Debian
• Gnu/linux
• Gentoo Linux
• Linpus Linux

To install a graphical interface or a command window, select:

In the server domain, there is really no need to run a graphical interface for the server. So we usually install the Linux operating system is often not installed graphical interface.

Although Linux and Microsoft Windows as the same-bit operating system, but they have a big difference is that the Windows operating system graphical interface is the kernel, commonly known as micro-kernel, and the Linux operating system graphical interface like a software, and the kernel is not one. So Linux you can choose not to install the graphical interface, so that not only does not affect the normal use of the server can also save system resources overhead

Linux System Overview and installation