1Java prerequisite knowledge (20210301)

What is a computer

Hardware and von Neumann structure

Computer hardware

Von Neumann architecture

Simple process of calculating and outputting 1+1

• Enter 1+1
• The arithmetic unit performs operations on 1+1 and puts the result in the memory
• Controller control output device output 2

Software and software development

Commonly used shortcut keys and Dos commands

Computer shortcuts

Ctrl+ C: Copy
Ctrl+ V: Paste
Ctrl+ A: Select all
Ctrl+ X: Cut
Ctrl+ Z: Undo
Ctrl+ S: Save
Alt+ F4: Close the window
Shift+ Delete: Permanently delete
Window+ r: Run; input cmd: Command window
Window+ e: Open the My Computer
Task Manager and turn off the desktop Drop: File-run new task-type'explorer'
Ctrl+ Shift+ Esc: open task manager
Windows+ Tab: switch application

Dos command

How to open CMD

1. Start+system+command prompt
2. Win+ R, Output cmd to open the console (recommended)
3. In any folder, press and hold Shift+ right-click with the mouse to open the command line window here
4. Add the cmd path in front of the address bar of the explorer
   

Run as administrator: start+system+command prompt+choose to run as administrator

Common Dos commands

1. Drive letter switch
   
2. View all files in the current directory: dir
   
3. Switch directory: cd (chage directory)
   cd… Return to the previous level
   
4. 清屏：cls（clear screen）
5. Exit the terminal: exit
6. View IP: ipconfig
7. Open the program
   calc: open the calculator
   mspaint: open the drawing
   notepad: open the notepad
8. ping command
   
9. Create folder md
   
10. Create and delete files
    
11. Remove file
    

Summarize file operations:
md directory name
rd directory name
cd> file name
del file name

The history of computer language

The first generation language-binary language

The second generation language-assembly language

Third-generation language