Concepts such as bit, byte, bit, byte, string, etc.

Original article: http://djt.qq.com/article/view/658

1. Ancient Messenger : Carriage, beacon, homing pigeon

2. In1837 , the world's first telegraph was born,

The American scientist, Moore, tries to use some "dots" and "strokes" to denote different letters, numbers, and punctuation marks, which are called "Morse codes" in a way that represents characters:

"Point" corresponds to a short electric pulse, "stroke" corresponds to a long electrical pulse signal, signal to each other, receiver translation

The decoder can be translated into English letters according to the combination of these dots, thus completing the communication task.

3. In1946 , the world's first computer was born, the computer used 8 transistors of "pass" or "break" a number of states to represent the world of all things.

The principle of the computer is simply the "point" and "row" in Morse code replaced by a 8-byte binary stream representation.

4. here, there are several basic concepts:

• bit (bit): Also known as "bit", the smallest unit in computer information is the abbreviation for binary digiT(binary digit) , which refers to a binary

• byte (byte): a unit of information metering in a computer, a bit representing "0" or "1", each 8 bits (bit) consisting of one byte (byte)
• The definition of VARCHAR in MySQL means 45 bytes

• character (Character): The general name of the text and the symbol, can be the text of each country, punctuation, graphic symbols, numbers, etc.

• Character Set (Character set): is a collection of multiple characters

• encoding (Encoding): The process of converting information from one form or format to another

• decoding (decoding): the inverse process of encoding

• character encoding (Character Encoding): What rules to store characters in

Now for our first telegram, Morse code contains symbols such as uppercase and lowercase letters and numbers.

• Each of these symbols is actually a ⌈ character ⌋
• The set of all the characters is called the ⌈ character set ⌋
• The correspondence between "point" or "stroke" and character can be called ⌈ character encoding ⌋.

5.3 Stages of coding development

In the case of phase one or two, an English character occupies one byte; a Chinese character occupies 2 bytes;

Concepts such as bit, byte, bit, byte, string, etc.