Getting Started with Linux basic 1_linux systems

the five main units of the computer

The five functional parts of computer hardware
Arithmetic device

An operator is also called an arithmetic logic unit (arithmetic logic units referred to as the ALU). It is the part of the computer to process the data, including arithmetic operations (addition, subtraction, multiplication, addition, etc.) and logical operations (with, or, non-, XOR, comparison, etc.).

Controller

The controller is responsible for removing the instruction from the memory and decoding the instruction, and according to the order of the instruction, it is responsible for issuing the control signal to the other parts, ensuring that the components work in a coordinated manner, and perform various operations step by step. The controller mainly consists of instruction register, decoder, program counter, operation Controller and so on.

The core of hardware system is CPU (central processing Unit). It is mainly composed of controllers, computing devices, and the use of large-scale integrated circuit technology made of chips, also known as microprocessor chips.

Memory

Memory is a part of a computer's memory or staging data. All the information in the computer, including the original input data. The initial processing of intermediate data and the final processing of useful information are stored in the memory. Furthermore, the various programs that command the computer's operation, that is, a set of instructions for how the input data is processed are also stored in the memory. Memory is divided into two types: internal memory (memory) and external memory (external memory).

Input device

The input device is the device that enters information to the computer. It is an important human-machine interface that converts the input information (including data and instructions) into binary code that can be recognized by the computer and feeds into the memory.

Output device

The output device is the device that outputs the computer's processing results. In most cases, it transforms these results into a form that is easy to identify.

Linux User Environment

Kernel (Kernel)

Kernel management issues are: System call interface (to achieve the communication between developers and the core), process control, reasonable allocation of CPU resources, memory management, file System management.

Shell

The shell is used to receive commands from the user and communicate with the kernel.

Terminal Simulator (Terminal Emulator)

X Window System

Window Manager (Windows Manager)

Desktop Environment (enviroment)

prompt with home directory

[Email protected] root]#

Explanation: [Login user name @ hostname current directory]# (# root user, $ normal user).

~: Home directory, which is the default directory after the user logs on to the system, equivalent to the Windows system's My Documents directory.

The root user's home directory is the directory, and the home directory for the general user is the home directory.

Create user

log in as the root user, Create the Jack user, after creation must use passwd create password to activate the user, if the root set password is too simple to prompt, if normal prompts repeatedly enter the confirmation password, the display setting is successful.

command:

useradd Jack . passwd Jack.

Effect:

Log in with the jack user you just created and change the password (if the password is too simple it will not change successfully)

Command:

su jack# Enter Password passwd #输入当前密码 # Enter new Password # Confirm enter new password

Effect:

Run Command

Directive name "Options" "Parameters"

LS: Show file directory

Ls-l: Listing More information

Ls-l Specify directory: Lists details for the specified directory

Effect:

Help and online Help

--help: for example LS--help.

Man command: e.g. man ls, Exit Press Q.

Info command: For example, Info ls, exit press Q.

the use of man skills

Man1 commands or executables that users can manipulate in a shell environment

Man2 functions and tools that can be called by the system kernel

Man3 Some common functions and libraries, most of which are C's function libraries

Description of the MAN4 device file, usually under/dec file

Man5 the configuration file or the format of some files

Man6 Games

MAN7 conventions and protocols, such as Linux file system, network protocol, ASCII code, and other instructions

MAN8 administrative commands available to system administrators

MAN9 files related to kernel

Getting Started with Linux basic 1_linux systems