What is digital data ?

Digital data is any data that can be represented using numbers. The most common application of digital data, today, is found inside a computer system. Computers can deal only with numbers - therefore, everything a computer displays, from the latest game to a web page, is, in reality, a series of numbers. This concept was nicely illustrated in the movie The Matrix.

Computers can only deal with special kinds of numbers called binary numbers. Binary numbers are made up of only two digits - zero (0) and one (1). So, the screen of information you are presently reading is, in reality, only a long series of zeros and ones.

What are binary numbers ?

Binary numbers are numbers written in the binary (base 2) number system. Our (base ten) number system uses the ten digits 0,1,2,3,4,5,6,7,8 and 9. The binary number system only uses the two digits 0 and 1.

Decimal Number	Binary Number
0	0
1	1
2	10
3	11
4	100
5	101
6	110
7	111
8	1000
9	1001
10	1010
11	1011
12	1100
13	1101
14	1110
15	1111

What can binary numbers be used for ?

Binary numbers may be used to represent various real world items. For example, binary numbers may be used to represent the letters of the alphabet.

Decimal Number	Binary Number	Letter
65	01000001	A
66	01000010	B
67	01000011	C
68	01000100	D
69	01000101	E
70	01000110	F
71	01000111	G

Using this code, we can translate a word like CAT into a string of binary digits

CAT = 01000011 010000001 01010100

We call this system of coding letters into strings of binary numbers the ASCII code. ASCII stands for American Standard Code for Information Interchange and is the system used by most computers.

Lots more information about binary numbers and ASCII can be »found here.