B
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B:
The designation for the second floppy disk drive in a PC. In earlier PCs that had two floppy drives, the 3.5" drive was typically A:, and the 5.25" drive was B:. Since the 5.25" floppy is obsolete, the B: is rarely seen anymore.
Baby AT motherboard
A smaller motherboard (9x10") that superseded the one used in the original IBM AT (12x13.5"). The Baby AT motherboard has been widely used in 386, 486 and Pentium PCs. It was superseded by the ATX motherboard. See ATX motherboard.
bin
(BINary) A popular directory name for storing executable programs, device drivers, etc. (binary files).
binary

Meaning two. The principle behind digital computers. All input to the computer is converted into binary numbers made up of the two digits 0 and 1 (bits). For example, when you press the "A" key on your personal computer, the keyboard generates and transmits the number 01000001 to the computer's memory as a series of pulses. The 1 bits are transmitted as high voltage; the 0 bits are transmitted as low. The bits are stored as charged and uncharged memory cells in the computer or as microscopic magnets on disk and tape. Display screens and printers convert the binary numbers into visual characters.

The electronic circuits that process these binary numbers are also binary in concept. They are made up of on/off switches (transistors) that are electrically opened and closed. The current flowing through one switch turns on (or off) another switch, and so on. These switches open and close in nanoseconds and picoseconds (billionths and trillionths of a second).

A computer's capability to do work is based on its storage capacity (memory and disk) and internal transmission speed. Greater storage capacities are achieved by making the memory cell or magnetic spot smaller. Faster transmission rates are achieved by shortening the time it takes to open and close the switch. In order to increase computer performance, we keep improving binary devices.


How Binary Numbers Work
Binary numbers are actually simpler than decimal numbers as they use only the digits 0 and 1 instead of 0 through 9.   Translating a binary number to decimal format is fairly easy.  Binary numbers are read left-to-right and are "place holders" for decimal numbers doubling in value starting at 1.  The following example is an 8-bit binary number of 11111111 and its corresponding decimal numbers for each of the 8 binary digits.

IE:  (   1        1       1        1      1        1       1       1   ) 
      ( 128     64      32     16      8        4       2       1   )

Now for all binary digits that are "OFF" (0) you skip and for all binary digits that are "ON"  (1), you add their decimal values together to get the total decimal value for that binary number.  In the next example you would add together the numbers 1 + 4 + 16 + 128 making the decimal translation of the binary number 10010101 to be 149.

IE:  (   1        0       0       1       0        1       0       1   ) 
      ( 128     64      32     16      8        4       2       1   )

Any positive number can be made with this method just by expanding or reducing the size of the above table by the number of digits in the binary number.
Binary
1
10
11
100
101
110
111		 Decimal
1
2
3
4
5
6
7		 Translation
1 = 1
2 = 2
1 + 2 = 3
4 = 4
1 + 4 = 5
2 + 4 = 6
1 + 2 + 4 = 7
binary values
The following table shows the maximum number of numeric combinations in a binary structure with all bits set to zero equivalent to one combination. For example, in one bit, which can be 0 or 1, there are two possible values.

Just as 99 is the largest decimal number in two decimal digits, 11 is the largest binary number in two binary digits. The decimal equivalent of the largest binary number in a group of bits is one less than the total number of values. For example, in four bits, which provides 16 values, the largest binary number is 1111 or 15 in decimal.

The decimal equivalent of the largest binary numbers as well as the binary numbers themselves are displayed below for up to 16 bits.

.
Bits Total Values       Largest binary number
Decimal equiv.                Binary
1
2
3
4

5
6
7
8

9
10
11
12

13
14
15
16

17
18
19
20

21
22
23
24

25
26
27
28

29
30
31
32

33
34
35
36

37
38
39
40		 2  [0 or 1]
4  [0, 1, 2 or 3]
8  [etc...]
16

32
64
128
256

512
1,024  (1K)
2,048  (2K)
4,096  (4K)

8,192  (8K)
16,384  (16K)
32,768 (32K)
65,536 (64K)

131,072 (128K)
262,144 (256K)
524,288 (512K)
1,048,576 (1M)

2,097,152 (2M)
4,194,304 (4M)
8,388,608 (8M)
16,777,216 (16M)

33,554,432 (32M)
67,108,864 (64M)
134,217,728 (128M)
268,435,456 (256M)

536,870,912 (512M)
1,073,741,824 (1G)
2,147,483,648 (2G)
4,294,967,296 (4G)

8,589,934,592 (8G)
17,179,869,184 (16G)
34,359,738,368 (32G)
68,719,476,736 (64G)

137,438,953,472 (128G)
274,877,906,944 (256G)
549,755,813,888 (512G)
1,099,511,627,776 (1T)

 1
3
7
15

31
63
127
255

511
1,023
2,047
4,095

8,191
16,383
32,767
65,535

1
11
111
1111

1 1111
11 1111
111 1111
1111 1111

1 1111 1111
11 1111 1111
111 111 11111
1111 1111 1111

1 1111 1111 1111
11 1111 1111 1111
111 1111 1111 1111
1111 1111 1111 1111
bit
(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.

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.

Bits are widely used as a measurement for transmission. Ten megabits per second means that ten million pulses are transmitted per second. A 16-bit bus means that there are 16 wires transmitting the bit at the same time.

Measurements for storage devices, 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 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 have been the pioneers in installing high-speed optical trunks throughout the country.
bit depth
(1) The number of bits used to hold a pixel. Also called "color depth" and "pixel depth," the bit depth determines the number of colors that can be displayed at one time. Digital video requires at least 15 bits, while 24 bits produces photorealistic colors.
.
Color depth Number of colors                                                
4-bits 16
8-bits 256
15-bits 32,768
16-bits 65,536
24-bits 16,777,216
32-bits 16,777,216 + alpha channel

.

(2) Bit depth can refer to any coding system that uses numeric values to represent something. The depth, or number of bits, determines how many discrete items can be represented.
bit specifications
Everything in the digital world is measured in bits and bytes. Bits are a measurement of different components and functions depending on what is being referenced. Following are the most common. See also binary values.

CPU
The size of the computer's internal registers (the computer's word size), which is the amount of data the CPU can compute at the same time. Theoretically, if the clock rates were the same (800MHz, 1GHz, etc.) and the basic architectures were equal, a 32-bit computer would work twice as fast internally as a 16-bit computer. In practice, 8-bit, 16-bit, 32-bit and 64-bit architectures are rarely identical to each other even from the same manufacturer. Thus, a 32-bit computer may be less than twice as fast or more than twice (internally) as fast as a 16-bit computer. This measurement also does not result in twice as much actual work being done for the user, as the computer's cache size and bus and disk speeds are all part of the performance equation.

System Bus
The size of the computer's system bus (frontside bus), which is the pathway over which data are transferred between memory and the CPU and between memory and the peripheral devices. If the bus clock rates are equal, a 32-bit bus transfers data twice as fast as a 16-bit bus.

Address Bus
The size of the address bus, which determines how much memory the CPU can address directly. Each bit doubles the number, for example, 20 bits addresses 1 megabyte (MB); 24 bits addresses 16 megabytes (MB); 32 bits addresses 4 gigabytes (GB). See binary values.

Color Depth
The number of colors that can be displayed at one time. This is called "bit depth," "color depth" and "pixel depth." Unless some of the memory is used for cursor or sprite movement, an 8-bit display adapter generates 256 colors; 16-bit, 64K colors; 24-bit, 16.8 million colors. See alpha channel and bit depth.

Bit specifications, such as 64-bit and 128-bit, refer to the display adapter's architecture, which affects speed, not the number of colors. See 64-bit graphics accelerator and 128-bit graphics accelerator.

Sound Sample
The quality of sound based on the number of bits in the samples taken. A 16-bit sample yields a number with 65,536 increments compared to 256 in an 8-bit sample. See 8-bit sample and 16-bit sample.
BNC connector
(Bayonet Neill-Concelman or British Naval Connector) A commonly used plug and socket for audio, video and networking applications. BNCs connect two-wire coaxial cable (signal and ground) using a bayonet mount. After the plug is inserted, the bayonet mechanism causes the pins to be pinched into the locking groove when the plug is turned.



BNC Connector BNCs differ from many connectors because of their snap-lock architecture, which keeps the plug firmly in its socket.
broadband
(1) High-speed transmission. The term is commonly used to refer to communications lines or services at T1 rates (1.544 Mbps) and above. The speed threshold of broadband is subjective and can be above or below T1. Some claim 45 Mbps is the starting point of broadband. In every case however, it implies transmitting at higher speeds than what was common before. Broadband often refers to Internet access using cable modems and DSL, both of which deliver speeds above and below T1. See T1, cable modem and DSL.

(2) A method of transmitting data, voice and video using frequency division multiplexing (FDM), such as used with cable TV. Modems are required to modulate digital data streams onto the line. Broadband in this context is used in contrast with baseband, which is all digital transmission and uses time division multiplexing (TDM). However, the term is mostly used in definition #1 above.
byte
(BinarY TablE) The common unit of computer storage from micro to mainframe. It is made up of eight binary digits (bits). A ninth bit may be used in the memory circuits as a parity bit for error checking. The term was originally coined to mean the smallest addressable group of bits in a computer, which has not always been eight.

A byte holds the equivalent of a single character, such as the letter A, a dollar sign or decimal point. For numbers, a byte can hold a single decimal digit (0 to 9), two numeric digits (packed decimal) or a number from 0 to 255 (binary numbers).

Byte Specifications
The primary specifications of hardware are rated in bytes; for example, a 40-megabyte (40M or 40MB) disk holds 40 million characters of instructions and data. A one-megabyte (1M or 1MB) memory allows one million characters of instructions and data to be stored internally for processing.

With database files and word processing documents, the file size is slightly larger than the number of data characters stored in it. Word processing files contain embedded codes for layout settings (margins, tabs, boldface); therefore, a 100,000-byte document implies slightly less than 100,000 characters of text (approx. 30 pages). Database files contain codes that describe the data fields within the records, thus, a 100,000-byte database file holds less than 100,000 characters of data.

Unlike data and text, a 100,000-byte graphics file is not indicative of the size of the image contained within. A 100,000 byte vector graphics file may render a very detailed and elaborate drawing, while a 100,000-byte bitmap file would be considerably smaller. Depending on the format, compression method and number of colors used, bitmapped images can range from a few thousand bytes up into the millions. See bit.

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