Initial knowledge of the operating system and Linux

initial knowledge of the operating system and Linux

1. The computer system consists of two parts: the hardware and software system , which is a modern intelligent electronic device which can receive and store information and process the massive data automatically and high-speed according to the program stored in it, and then output the processing result.

2. the world's first computer was born in 1946 at the University of Pennsylvania in the United States.

3. von Neumann architecture : 1946 the mathematician von Neumann put forward the computer hardware system by the arithmetic device, the controller, the memory, the input device, the output equipment. Morgan's Law: When the price is constant, the number of components that can be accommodated on the IC is increased by a factor of about every 18-24 months, and the performance will be boosted by one more. Now computer technology is difficult to follow the second law, the future will go to the development of quantum computers .

4. servers (server) are computers that are high-performance computers that provide a variety of services to client computers in the network

Server by Type: Tower Server,

Rack Server (Rack server width is 19 inches (48.26cm), Height in u 1u=1.75 inch = 44.45 mm, usually 1u,2u, 3U, 4U, 5U, 7U of several standard servers. The size of the cabinet is also used in general industry standards. The largest number of servers sold at this stage)

Blade Type server:

By application function: Wed server, database server, mail server, file server, ERP server and so on.

Server CPU Company:

Intel:xeon Xeon Itanium itanium®

Amd:althlon MP (Few people use it now)

Ibm:power (basic their own company use)

The types of CPUs are:

x86

X64 (CISC)

ARM (Acorn RISC machine)

m68000, m68k (moto)

Power (IBM)

Powerpc (Apple, Ibm,moto)

Ultrasparc (Sun)

Alpha (HP)

Itanium (Compaq)

The server can be divided by the number of CPUs:

4-Way and 4-way servers (Enterprise Servers)

2-Way Server (departmental server)

1-Way Server (entry-level server)

The server hard disk interface is generally a SAS interface and also supports SATA interfaces. SSD interface is now supported

Server Performance Short board: In the computer system, the read-write rate of the hard disk has become the bottleneck that affects the performance of the system further.

Storage network:

das-– directly connected storage (direct attached Storage) storage device tightly connected to the host

NAS-Networked storage (network attached Storage) connects multiple file servers via LAN, file-based protocol (NFS, smb/cifs) for file sharing

san-– Storage Areas Network (Storage area Networks) utilizes high-speed fiber-optic network-linked servers and storage devices, based on high-level protocols such as SCSI, IP, ATM, and more, enabling storage

Operating System (OS): (1) Kernel functions: Process management, memory management, security management, network management, file management, hardware mechanism.

(2) OS classification:

Server Os:rhel, Centos,windows Server,aix

Desktop Os:windows 10,windows 7,mac OS, Fedora

Mobile device Os:andriod,ios,yunos

Free software means: free learning, free modification, free access. (does not mean free)

The development history and three major distributions of Linux: 1. Redhat 2.debian 3.Gentoo 4.LFS (Homemade Linux)

Development history can be online query to understand;

The philosophical Thinking of Linux: 1. All documents;

2. A small program consisting of a single purpose, combining small procedures to complete complex tasks;

3. Try to avoid capturing the user interface;

4. The configuration file is saved in plain text format;

Get the release version of CentOS:

Https://wiki.centos.org/Download

Http://mirrors.aliyun.com

Http://mirrors.sohu.com

Http://mirrors.163.com

LINUX2 Large Interface:

GUI interface: Graphical User Interface
CLI interface: Command-Line interface

command format : command option parameter

# Command Options ... arguments ...
Options:
Short Options: –
Multiple options can be combined:-a-b =-ab
Long options:-

parameters : The Action object of the command
Virtual Terminal (terminal): Ctrl+alt+f1-f6
Analog Terminal: Terminal in GUI graphical interface

Beginner to install Linux with VM VMS: Installation process note Do not minimize installation, a hard disk up to 4 primary partitions, extended partitions can be more than one, the installation process can use CTRL+ALT+F2 to enter the command line to view the installation progress, cat/etc/proc/ Partitions can view the partition situation, Cat/etc/meminfo can view the memory, ctrl+alt+f3 the viewing process, Ctrl+alt+f6 back to the installation interface. (use English as much as possible during installation.)

Directory Structure Differences

Linux

/

USR application

Home Directory

Dev device files

LIB64 Library file

Etc=edit config configuration file and binary file

Boot boot kernel

Proc Process processes

SYS system

Opt Software Installation directory

MNT Mount Mount

A few small commands for the first contact:

Cat/proc/cpuinfo

LSCPU List CPU Information

Cat/proc/meminfo

Free lists memory information

Cat/proc/partitions Partition information

Cat/proc/swaps

Lsb_release

Uname-r Kernel Information

Df

WhoAmI

Who am I current user

TTY Display current terminal number

Init 3 Character interface (Close graphical interface)

Init 5 Graphical interface (open graphical interface)

Init 0 shutdown

Init 6 reboot Restart

Initial knowledge of the operating system and Linux