A bit is a unit of information having two states (true or false, one or zero). A byte is a unit of information usually equal to 8 bits and a nibble (less commonly used) is equal to 4 bits. A bit rate is a unit of bits transferred per unit of time (bit/second).
History
- 1732: The encoding of data by discrete bits was used in the punched cards invented by Basile Bouchon and Jean-Baptiste Falcon.
- 1804: The bits are now developed by Joseph Marie Jacquard.
- 1844: The bits were later adopted by Semyon Korsakov, Charles Babbage, Hermann Hollerith, and early computer manufacturers like IBM. A variant of that idea was the perforated paper tape. In all those systems, the medium (card or tape) conceptually carried an array of hole positions; each position could be either punched through or not, thus carrying one bit of information. The encoding of text by bits was also used in Morse code.
- 1870: The encoding of text by bits was also used in early digital communications machines such as teletypes and stock ticker machines.
- 1928: Ralph Hartley suggested the use of a logarithmic measure of information.
- 1936: Vannevar Bush had written of "bits of information" that could be stored on the punched cards used in the mechanical computers of that time. The first programmable computer, built by Konrad Zuse, used binary notation for numbers.
- 1947: He attributed its origin to John W. Tukey, who had written a Bell Labs memo on 9 January 1947 in which he contracted "binary information digit" to simply "bit".
- 1948: Claude E. Shannon first used the word "bit" in his seminal paper "A Mathematical Theory of Communication".
Power of 10 Multiples of One Bit
| Name
|
Abbreviation
|
Bits
|
Bytes
|
Relation to Previous
|
| Bit
|
b
|
1
|
0.125
|
|
| Kilobit
|
kb
|
103
|
1.25 × 102
|
1000 b
|
| Megabit
|
Mb
|
106
|
1.25 × 105
|
1000 kb
|
| Gigabit
|
Gb
|
109
|
1.25 × 108
|
1000 Mb
|
| Terabit
|
Tb
|
1012
|
1.25 × 1011
|
1000 Gb
|
| Petabit
|
Pb
|
1015
|
1.25 × 1014
|
1000 Tb
|
| Exabit
|
Eb
|
1018
|
1.25 × 1017
|
1000 Pb
|
| Zettabit
|
Zb
|
1021
|
1.25 × 1020
|
1000 Eb
|
| Yottabit
|
Yb
|
1024
|
1.25 × 1023
|
1000 Zb
|
| Ronnabit
|
Rb
|
1027
|
1.25 × 1026
|
1000 Yb
|
| Quettabit
|
Qb
|
1030
|
1.25 × 1029
|
1000 Rb
|
Binary Multiples of One Bit
| Name
|
Abbreviation
|
Bits
|
Bytes
|
Relation to Previous
|
| Bit
|
b
|
1
|
0.125
|
|
| Kibibit
|
Kib
|
210
|
27
|
1024 b
|
| Mebibit
|
Mib
|
220
|
217
|
1024 Kib
|
| Gibibit
|
Gib
|
230
|
227
|
1024 Mib
|
| Tebibit
|
Tib
|
240
|
237
|
1024 Gib
|
| Pebibit
|
Pib
|
250
|
247
|
1024 Tib
|
| Exbibit
|
Eib
|
260
|
257
|
1024 Pib
|
| Zebibit
|
Zib
|
270
|
267
|
1024 Eib
|
| Yobibit
|
Yib
|
280
|
277
|
1024 Zib
|
| Robibit
|
Yib
|
290
|
287
|
1024 Yib
|
| Quebibit
|
Qib
|
2100
|
297
|
1024 Rib
|