- Bandwidth
- There are physical constraints on the amount of data that can be transferred
through a specific medium. The constraint is measured in terms of the
amount of data that can be transferred over a measure of time, and is
known as the bandwidth of the particular medium. Bandwidth is
measured in bps (bits per second).
- BBS
- Bulletin Board System
- The father of newsgroups. A BBS allows one to 'paste' messages on an
electronic bulletin board. The FTP service
is usually also available on BBS's.
- Berkeley Internet Name Domain
- See BIND
- Berkeley Software Distribution, Inc
- See BSDI
- Binary
- Computer software uses binary mathematics based on whether an electric
current in the hardware is on or off in the circuitry. Zero means it
is off, one means it is on.
- This on-off system is called the bit system
(short for binary digit).
- Binary digit
- See bit
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- BIND
- Berkeley Internet Name Domain
- BIND is an Internet Domain Name Service allowing aliasing of IP numbers
(such as 197.45.67.176) to human recognizable names (such as www.wacko.org).
- Bit
- Binary digit
- A bit is the smallest unit that is measured in digital computing systems.
The bit relates to the on/off status of a processor. Eight bits make
up one byte. The architecture of early personal computers
was such that they could handle larger units than bits, namely eight
bits at a time. This larger unit is called a byte. The early
computers were thus 8-bit or 1-byte machines. Later machines could handle
16-bits or 2-bytes. The technology is now at the stage where PCs can
handle 32-bit words and larger Unix-based systems 64-bits.
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- Bitmap graphic
Also see Raster
- A bitmap graphic is a pixel-based model for displaying images on display
units such as computer and TV screens. A bitmap graphic contains data about
the color and coordinates of each pixel that needs to be triggered on the
computer screen. Strictly speaking bitmap graphics are not bitmaps, but
pixelmaps.
Bitmaps on computer screens
Bitmap graphic files are typically huge, so for better computer network
transport they are compressed. The most typical bitmap compression methods
on the Web are GIF, JPEG
and PNG.
- Another method for displaying images on computer screens is vector
graphics.
- Bitmap file
- A bitmap file contains the data for a bitmap image in bit-format. It usually
consists of a Header and Bitmap Data. If a file contains no image data,
only a header will be present. If additional information is required that
does not fit in the header, a footer will usually be present as well. Palette
data may also me used, which typically follows the Header.
- Here is a summary of the bitmap file content structure:
- bitmap-file header: this contains information
about the type, size, and layout of a device-independent bitmap file.
- bitmap-information header: which specifies
the dimensions, compression type, and color format for the bitmap.
- colour table: defined as an array of RGBQUAD
structures, contains as many elements as there are colours in the bitmap.
The colour table is not present for bitmaps with 24 color bits because
each pixel is represented by 24-bit red-green-blue (RGB) values in the
actual bitmap data area.
- image data: array of bytes that defines the
bitmap bits. These are the actual image data, represented by consecutive
rows, or "scan lines," of the bitmap. Each scan line consists of consecutive
bytes representing the pixels in the scan line, in left-to-right order.
- Bits per second
- See BPS
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- BOM
- Byte Order Mark
- BOM is used with UTF-16 characters to avoid
confusion with UTF-8 characters.
- BPS
- Bits per second
- Bits per second refers to the number of bits transferred per a second
through a medium. This unit of measurement is used to determine the bandwidth of
the medium.
- Bridge
- Bridge is a network related term.
A bridge operates on the Data Layer of the OSI model.
A bridge keeps a record of each connected network segment. Bridges can
be used for different protocols and serve as a filtering mechanism. Because
the filter of a bridge can be configured to allow or disallow certain
types of information, it forwards or stops frames for pre-determined
network segments.
- Also see router and gateway.
- Brightness
- Brightness (or value) is achieved by adding
white or black to the basic color hue. Adding white adds to brightness,
while adding black makes it duller, thus having less brightness. The color
white has maximum brightness, while the color black has minimum brightness.
Technically white is the presence of all potential light, while black is
the absence of light.
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- Browser
- A browser is a software program that interprets markup documents
(such as HTML) and renders them visually on
computer screens. At present the most common way to access The Internet
is by means of a visual browser.
With
the
advent of other media devices a browser is merely one of the ways used
for accessing The Internet. As The Internet can be accessed by means
of other media, such as audio, and in future smelling and touching, it
is technically more correct to rather speak of a User Agent than
of a browser. There are many browsers other than Netscape or Internet
Explorer available for PCs, and there are "browsers", i.e user agents,
for other types of visual devices, such as handheld devices, projection
screens
and others.
A parser (which is a part of a browser) investigates
the elements and their relationships and determines the
structure of the document. This is done on the bases
of marked document objects. For example, in HTML paragraphs
are marked as such with the <p>...</p> tag set. The parser
then passes that information along to a rendering engine
which
manipulates
the content, typically using associated style sheets
to determine how the content is to be rendered. The most
typical manipulation is to display the content graphically
on a computer screen, but it could also be manipulated
to be rendered on other types of devices, such as speech
synthesizers or tactile devices (eg Braille devices).
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- BSDI
- Berkeley Software Distribution, Inc
- BSDI is a flavor of Unix originally developed at the University of
California, Berkeley Campus.
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- Bulletin Board System
- See BBS
- Byte
- A byte is a unit of measurement of data size. One byte consists of
8 bits. One ASCII character
is one byte in size
8-bit system
| bits |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
| byte |
1 |
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- Byte Order Mark
- See BOM
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