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drill

, tool
drill, tool used to create a hole, usually in some hard substance, by its rotary or hammering action. Many different tools make up the drill family. The awl is a pointed instrument used for piercing small holes. In its early form it was a thorn or a tool of bone or chipped flint; many prehistoric awls of flint have been found. The gimlet, which consists of a cross handle holding a metal shaft with a screw point, is used for boring small holes. Its principle and that of a similar tool, the auger, were known and used in ancient times, but the tools were much improved in the Middle Ages. The auger has a cross handle containing a shaft that usually ends with a central screw-shaped point; the point acts to pull two knife edges about it into the material to do the actual cutting. Spiral channels extend part way up the shaft to allow chips to be removed from the hole. The term auger is also applied to various augerlike tools. More elaborate types of drills are composed of two main parts: a replaceable device that does the actual cutting, called a bit, and a second device that drives it. Both devices may be referred to as drills. Two common types of rotary bits are the auger and the twist bit. Hand-powered rotary driving devices include the hand drill, which has a crank that transmits turning power to the bit through a gear and pinion, and the bit brace, which is a bow-shaped device that is rotated to turn a bit. Motor-powered rotary driving devices include the drill press and the portable electric drill, both used at home or in industry for cutting holes in such materials as metal, wood, and plastic. The core drill cuts an annular hole through minerals. For a small hole the drill bit may contain diamonds, which bore a hole by their abrasive action when they are rotated. A rotary oil well drill uses a bit containing either rolling cutters with hard teeth or a fixed, chisel cutting edge. The percussive types of drill force a bit to move forward by a hammering action that chips away material, instead of cutting or abrading it. For example, an air percussion drill chips through rock with a cross-shaped bit driven by a piston; the similar churn drill is lifted and dropped by cable. One special kind of drill, the fusion drill, creates a hole by melting or flaking minerals with an oxyacetylene torch. An agricultural implement for planting certain seeds or for placing fertilizer in the soil is called a drill. Small drills for gardens are pushed by hand; large drills for field work are drawn by horses or tractors. The agricultural drill is named for its special uses, e.g., the grass drill and the grain drill, or for its construction, as the disk drill and the hoe drill. The fertilizer drill is commonly combined with the seed drill.
The Columbia Electronic Encyclopedia™ Copyright © 2022, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Bit

 

part of the bridle of a horse’s harness. Bits appeared in the late Bronze Age, when the horse was first used as a beast of burden. Originally they were made of soft material (sinew) and were secured in the horse’s mouth by bone cheekpieces. Bronze bits and cheekpieces appeared at the turn of the first millennium B.C., and iron bits were prevalent in the seventh and sixth centuries B.C. Iron snaffles with movable rings at the ends were used in Rus’. In the late Middle Ages, bits were very intricate and sometimes richly ornamented. Modern bits consist of two parts and have snaffle rings.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

bit

[bit]
(computer science)
A unit of information content equal to one binary decision or the designation of one of two possible and equally likely values or states of anything used to store or convey information.
A dimensionless unit of storage capacity specifying that the capacity of a storage device is expressed by the logarithm to the base 2 of the number of possible states of the device.
(design engineering)
A machine part for drilling or boring.
The cutting plate of a plane.
The blade of a cutting tool such as an ax.
A removable tooth of a saw.
Any cutting device which is attached to or part of a drill rod or drill string to bore or penetrate rocks.
(mathematics)
In a pure binary numeration system, either of the digits 0 or 1. Also known as bigit; binary digit.
(metallurgy)
In soldering, the portion of the iron that transfers either heat or solder to the joint involved.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Bit

A binary digit. In the computer, electronics, and communications fields, “bit” is generally understood as a shortened form of “binary digit.” In a numerical binary system, a bit is either a 0 or 1. Bits are generally used to indicate situations that can take one of two values or one of two states, for example, on and off, true or false, or yes or no. If, by convention, 1 represents a particular state, then 0 represents the other state. For example, if 1 stands for “yes,” then 0 stands for “no.”

In a computer system a bit is thought of as the basic unit of memory where, by convention, only either a 0 or 1 can be stored. In a computer memory, consecutive bits are grouped to form smaller or larger “units” of memory. Depending upon the design of the computer, units up to 64 bits long have been considered. Although there is common agreement as to the number of bits that make up a byte, for larger memory units the terminology depends entirely on the convention used by the manufacturer. In all of these units the leftmost bit is generally called the most significant bit (msb) and the rightmost the least significant bit (lsb).

Bytes and larger units can be used to represent numerical quantities. In these cases the most significant bit is used to indicate the “sign” of the value being represented. By convention a 0 in the msb represents a positive quantity; a 1 represents a negative quantity. Depending on the convention used to represent these numbers, the remaining bits may then be used to represent the numerical value. In addition to numerical quantities, bytes are used to represent characters inside a computer. These characters include all letters of the English alphabet, the digits 0 through 9, and symbols such as comma, period, right and left parentheses, spaces, and tabs. Characters can be represented using ASCII (American Standard Code for Information Interchange) or EBCDIC (Extended Binary Coded Decimal Interchange Code). The latter is used by some mainframe computers. Computers are set up to handle only one of these two character codes. Generally, the internal representation of a character is different in the two codes. For instance, in ASCII the plus sign is represented by the numerical sequence 00101011, and in EBCDIC, by 01001110.

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.

bit

bit, 1
1. A small tool which fits in the chuck of a brace or drill, and by which it is rotated—thereby cutting or boring a hole.
2. The projecting blade of a key which is cut in a manner to actuate the tumblers and permit the lock bolts to be operated.
3. That part of a soldering iron which transfers heat and solder to the joint.
4. The cutting edge of a plane.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

bit

1
1. a metal mouthpiece, for controlling a horse on a bridle
2. a cutting or drilling tool, part, or head in a brace, drill, etc
3. the blade of a woodworking plane
4. the part of a pair of pincers designed to grasp an object
5. the copper end of a soldering iron
6. the part of a key that engages the levers of a lock

bit

2 Maths Computing
1. a single digit of binary notation, represented either by 0 or by 1
2. the smallest unit of information, indicating the presence or absence of a single feature
3. a unit of capacity of a computer, consisting of an element of its physical structure capable of being in either of two states, such as a switch with on and off positions, or a microscopic magnet capable of alignment in two directions
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

bit

(unit)
(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.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

bit

(1) (Built-In Test) See BIST.

(2) (BInary digiT) The smallest element of computer storage. The bit is a single digit in a binary number containing only 0s and 1s. Physically the bit is a transistor and capacitor in a RAM cell, a magnetic domain on disk or tape, a cell in a solid state drive (SSD), a spot on optical media or a voltage pulsing through a circuit.

Transmitting Bits
Bits are used as a measurement for network transmission. For example, one hundred megabits per second (100 Mbps) means that 100 million pulses are transmitted per second. See space/time.

Storing Bytes
Eight bits make up a "byte," which is manipulated as one entity. Each byte can store one alphanumeric character, one decimal digit or a decimal number from 0 to 256 (see binary number and binary values). Measurements of files, databases, storage drives and memory (RAM) are given in bytes rather than bits. See space/time, byte and word.


Storage - Making it Smaller
Making the spot or cell smaller increases the storage capacity. Today's storage drives hold staggering amounts of data compared to 10 years ago. For a fascinating storage technology that never became popular, see holographic storage.


Storage - Making it Smaller
Making the spot or cell smaller increases the storage capacity. Today's storage drives hold staggering amounts of data compared to 10 years ago. For a fascinating storage technology that never became popular, see holographic storage.







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, illustrated here as a mechanical switch. Transmitting pulses within the computer is much simpler than over an external network where they are influenced by distance and interference. However, the telephone companies pioneered optical trunks, which overcame these limitations.
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