The binary number system and the character
The binary number system uses eight bits arranged into 256 combinations (28) to represent different characters.
Eight bits form a Byte. Since characters are stored using a byte 1, we commonly refer to bytes as character bytes.
The following characters are represented by the corresponding bytes in a computer:
|
Byte (8bits) |
Character |
|
0100 0001 |
A (Upper case) |
|
|
|
|
0110 0001 |
a (Lower case) |
|
|
|
|
0000 1001 |
Horizontal tab |
|
|
|
|
0010 0000 |
Blank space |
|
|
|
|
0001 1011 |
Escape |
|
|
|
|
0100 0000 |
@ |
The Horizontal Tab, which moves the cursor a given number of spaces, and the Escape character, which indicates to devices that a control code follows, are both below 0100 00002 (32 decimal) and are therefore used for control and are not printable text.
- There are slight variations in the way characters are defined as a numeric code in binary systems used by computers.
- The American Standard Code for Information Interchange (ASCII) is the name of the most popular character set in use in PC's.
More about the byte:
- True ASCII only uses 7 bits but the PC as introduced by IBM used an extended character set which used all of the 256 combinations.
