Basic knowledge of software and hardware -- diary (1)

        Finally, I finished reading two books, software engineering and software testing technology guide , Because it's self-study, I always feel like I forget before I learn . Sometimes I don't feel ashamed to ask my husband , He is always perfect to ask me speechless .. I accidentally flipped the video of dark horse program yesterday , I think it is very suitable for me 0 Basic little white ... Then there is today's diary .

One 、 Computers can be abbreviated as PC

Two 、 The characteristics of computers

        1、 It can be calculated mathematically and logically

        2、 Can store and remember

        3、 Efficient automatic operation （ According to program instructions ）

3、 ... and 、 The components of a computer

hardware system ：

        1、 input device

        2、 Output devices

        3、 Arithmetic unit 、 controller （ finger CPU）

        4、 Memory

            （1） Memory ： Data loss after power failure （ Memory runs faster than external memory ）

            （2） External storage ： Data retention after power failure

software system

1、 software system

(1) Desktop operating system （PC End ）windows( Large users ）Macom( Apple system ）

Linux( Less application software , however IT Systems that people must master ）

（2） Mobile system ：Android、ios

（3） Server system ：Linux( Open source 、 Stable 、 free 、 Large users ）Windows Serve( charge 、 Users less ）

2、 Application software ： In addition to the operating system software , Are all application operations （ Such as WeChat 、QQ、APP etc. ）

Four 、 Binary in a computer

At the bottom of the computer CPU Can only identify 0 and 1, here 1 It means true （ high voltage ）0 On behalf of false （ Low voltage ） Binary can be converted to decimal .

5、 ... and 、 The development of computer language

Machine code 、 machine language （0、1）

assembly language ： The syntax is simplified on the basis of machine code , Some English words are used to express the purpose of the program , Finally, it is converted into 0 and 1 Let the machine recognize .

High-level language ：Java、C、C++、php etc.

Be careful ： Assembly language is closest to machine code , It runs faster than high-level languages .

6、 ... and 、 Coded character set

UTF-8 Only in Chinese , Try to use this code set . It stands for international code

7、 ... and 、 A common unit of a computer

1、 The bit （bit position ）： The minimum unit of measurement artificially specified

2、 byte （bytes）: Artificially specified unit , One byte is equal to 8 position

1B=8b

1KB=1024B

1MB=1024KB

1GB=1024MB

1TB=1024GB

1PB=1024TB

8、 ... and 、dos command

Write code to achieve the purpose of the control system

1、win+R Open the run window

2、 Writing cmd Enter or confirm 、 The window will open 、 Write code to control

3、ipcomfig/all enter

      Check the network connection of the current computer ;

      Find Ethernet Ethernet or local connection , Find the physical address in the following values （ Also called MAC Address ） And then a string of numbers , It is also the unique identification code of this machine .

4、ping website enter   View current calls and logs Web address network connectivity status

5、 Drive letter with colon   Example ：F: Toggle character

 

6、cd The name of the catalog （ Folder name ） Enter the specified folder

 7、cd..  Return to the previous directory （ Folder ）

 

 8、cd/    Return to root （ The top directory is usually C\D\F disc ）