Digital circuits (i) Computer history, numerical and code systems

I. Computer history generation constitutes the first generation computer vacuum tube computer (ENIAC) second generation computer transistor computer third generation computer Integrated circuit fourth generation computer large-scale (LSI) and VLSI (VLSI)

Second, the composition of the computer hierarchy level system level Register class Gate level transistor level physics class

Iii. composition and structure of the computer
Input, Arithmetic/logic unit (ALU), storage unit, control unit

Iv. Numerical and code systems
1, complement: Take the counter plus a
2, floating-point number n=mxre
3. ASCII code
U.S. Information Interchange standard code symbol value 0 A 97

4, Gray code numerical value gray code number gray code 0 0000 15 1000 1 0001 14 1001 2 0011 13 1011 3 0010 12 1010 4 0110 11 1110 5 0111 10 1111 6 0101 1 7 0100 8 1100

This table can be summed up the law
A total of 16 numbers, the top two about the first symmetry; the first two of the first four are symmetric with the latter two on the second, the first four in the first eight with the latter four in relation to the third, and the 16 numbers in the first eight with the latter eight on the fourth-bit symmetry.
This law can easily write gray code table.
5, the Han-hamming

。。。 Not to be continued ...