Remember that a byte represents one character of information; four bytes are needed to represent a string of four characters. The following four bytes represent the text string 12AB (using ASCII code):
00110001 00110010 01000001 01000010 1 2 A B
The following illustrates how the binary language spells the word "binary":
B I N A R Y 01000010 01001001 01001110 01000001 01010010 01011001
It is very important to understand that in computer processing the "space" is a significant character. All items in a code must be set out for the machine to process. Like any other character, the space has a binary value that must be included in the data stream. In computing, the absence or presence of a space is critical and sometimes causes confusion or frustration among new users. Uppercase and lowercase letters also have different values. Some operating systems (for example, UNIX) distinguish between them for commands, while others (for example, MS-DOS) translate the uppercase and lowercase into the same word no matter how it is cased.
The following table is a complete representation of the ASCII character set. Even in present-day computing, laden with multimedia and sophisticated programming, ASCII retains an honored and important position.
|Symbol||Binary 1 Byte||Decimal||Symbol||Binary 1 Byte||Decimal|
All letters have a separate ASCII value for uppercase and lowercase. The capital letter "A" is 65, and the lowercase "a" is 97.
Keep in mind that computers are machines, and they do not really perceive numbers as anything other than electrical charges setting a switch on or off. Like binary numbers, electrical charges can exist in only two states-positive or negative. Computers interpret the presence of a charge as one and the absence of a charge as zero. This technology allows a computer to process information.