bit

bit: see drill.

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bit

 in full binary digit

In communication and information theory, a unit of information equivalent to the result of a choice between only two possible alternatives, such as 1 and 0 in the binary code generally used in digital computers. It is also applied to a unit of memory corresponding to the ability to store the result of a choice between two alternatives. A byte consists of a string of eight consecutive bits and makes up the basic information processing unit of a computer. Because a byte includes only an amount of information equivalent to one letter or one symbol (e.g., a comma), the processing and storage capacities of computer hardware are usually given in kilobytes (1,024 bytes), megabytes (1,048,576 bytes), and even gigabytes (about 1 billion bytes) and terabytes (1 trillion bytes).

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(BInary digiT) The smallest element of computer storage. It is a single digit in a binary number (0 or 1). The bit is physically a transistor or capacitor in a memory cell, a magnetic domain on disk or tape, a reflective spot on optical media or a high or low voltage pulsing through a circuit.

Bits for Transmission
Bits are widely used as a measurement for network transmission. One hundred megabits per second means that 100 million pulses are transmitted per second.

Bytes for Storage
Groups of bits make up storage units in the computer, called "characters," "bytes," or "words," which are manipulated as a group. The most common is the byte, made up of eight bits and equivalent to one alphanumeric character. Measurements for storage components, such as disks, files and databases, are given in bytes rather than bits. See space/time.

Storage - Making it Smaller

Making the spot or cell smaller increases the storage capacity. Our disks hold staggering amounts of data compared to 10 years ago, yet we still want more. Look up holographic storage for a look into a fascinating future of storage technology.

Transmission - Making it Faster

The bit is transmitted as a pulse of high or low voltage. Speed is increased by making the transistors open and close faster, which is a combination of making the microscopic elements within the transistor smaller and more durable.

Transmitting pulses internally in the computer is much simpler than out over a network, where they are influenced by long distances and interference. The telephone companies pioneered the deployment of high-speed optical trunks, which overcome some of these limitations.

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(unit)

bit - (b) binary digit. The unit of information; the amount of information obtained by asking a yes-or-no question; a computational quantity that can take on one of two values, such as false and true or 0 and 1; the smallest unit of storage - sufficient to hold one bit. A bit is said to be "set" if its value is true or 1, and "reset" or "clear" if its value is false or 0. One speaks of setting and clearing bits. To toggle or "invert" a bit is to change it, either from 0 to 1 or from 1 to 0. The term "bit" first appeared in print in the computer-science sense in 1949, and seems to have been coined by the eminent statistician, John Tukey. Tukey records that it evolved over a lunch table as a handier alternative to "bigit" or "binit". See also flag, trit, mode bit, byte, word.