Computers are digital and can therefore just distinguish for a bit between two conditions. Various synonyms are possible for the condition of a digital signal:
1 and 0
true and false
set and reset
or for the hardware people low and high
To deal with bits, sequential bits are grouped together:
Number of bits |
Name |
Combinations |
Commonly used for |
4 |
nibble |
16 |
Hexadecimal character |
8 |
byte |
256 |
ASCII character |
16 |
word |
65536 |
Integer numbers |
The 16 bit combinations the following characters are assigned:
Bit combination |
Representing character |
|||
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
|
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
1 |
0 |
2 |
0 |
0 |
1 |
1 |
3 |
0 |
1 |
0 |
0 |
4 |
0 |
1 |
0 |
1 |
5 |
0 |
1 |
1 |
0 |
6 |
0 |
1 |
1 |
1 |
7 |
1 |
0 |
0 |
0 |
8 |
1 |
0 |
0 |
1 |
9 |
1 |
0 |
1 |
0 |
A |
1 |
0 |
1 |
1 |
B |
1 |
1 |
0 |
0 |
C |
1 |
1 |
0 |
1 |
D |
1 |
1 |
1 |
0 |
E |
1 |
1 |
1 |
1 |
F |
The human brain has to remember just 16 combinations to convert a nibble to a bit sequence. A byte contains two nibbles and instead of representing it as a decimal number, it can be represented as two nibbles and therefore two hexadecimal numbers.
Observing a memory dump or any file (as an example to see character encoding) ghex to have a hex editor or a simple hex converter, to start type ghex2.
Alternatives are: lfhex, hexer, hexedit, hexcurse, wxhexeditor.
Mysterious things can be observed:
carriage return (cr) line feed (lf) or carriage return (cr) only (=Unix style) at line ends
tabs or spaces used
utf-8 character encoding