bit slice definition
<architecture> A technique for constructing a processor from
modules, each of which processes one bit-field or "slice" of
an operand. Bit slice processors usually consist of an
ALU of 1, 2, 4 or 8 bits and control lines (including
carry or overflow signals usually internal to the CPU).
For example, two 4-bit ALUs could be arranged side by side,
with control lines between them, to form an 8-bit ALU. A
sequencer executes a program to provide data and control
signals.
The AMD Am2901 is an example.
(1994-11-15)
Nearby terms:
bit rate « bit-robbing « bit rot « bit slice » bits per inch » bits per pixel » bits per second
bits per inch definition
<unit> (BPI) A measure of the recording density of a magnetic
tape or disk.
(1995-04-13)
Nearby terms:
bit-robbing « bit rot « bit slice « bits per inch » bits per pixel » bits per second » bit string
bits per pixel definition
<hardware, graphics> (bpp) The number of bits of information
stored per pixel of an image or displayed by a graphics
adapter. The more bits there are, the more colours can be
represented, but the more memory is required to store or
display the image.
A colour can be described by the intensities of red, green and
blue (RGB) components. Allowing 8 bits (1 byte) per
component (24 bits per pixel) gives 256 levels for each
component and over 16 million different colours - more than
the human eye can distinguish. Microsoft Windows [and
others?] calls this truecolour. An image of 1024x768 with
24 bpp requires over 2 MB of memory.
"High colour" uses 16 bpp (or 15 bpp), 5 bits for blue, 5 bits
for red and 6 bits for green. This reduced colour precision
gives a slight loss of image quality at a 1/3 saving on
memory.
Standard VGA uses a palette of 16 colours (4 bpp), each
colour in the palette is 24 bit. Standard SVGA uses a
palette of 256 colours (8 bpp).
Some graphics hardware and software support 32-bit colour
depths, including an 8-bit "alpha channel" for transparency
effects.
(1999-08-01)
Nearby terms:
bit rot « bit slice « bits per inch « bits per pixel » bits per second » bit string » bit stuffing
bits per second definition
<communications, unit> (bps, b/s) The unit in which data
rate is measured.
For example, a modem's data rate is usually measured in
kilobits per second. In 1996, the maximum modem speed for
use on the PSTN was 33.6 kbps, rising to 56 kbps in 1997.
Note that kilo- (k), mega- (M), etc. in data rates denote
powers of 1000, not 1024.
(2002-03-23)
Nearby terms:
bit slice « bits per inch « bits per pixel « bits per second » bit string » bit stuffing » bit twiddling
bit string definition
<programming, data> An ordered sequence of bits. This is
very similar to a bit pattern except that the term "string"
suggests an arbitrary length sequence as opposed to a
pre-determined length "pattern".
Nearby terms:
bits per inch « bits per pixel « bits per second « bit string » bit stuffing » bit twiddling » bitty box
bit stuffing definition
<protocol> A protocol which guarantees the receiver of
synchronous data can recover the sender's clock. When the
data stream sent contains a large number of adjacent bits
which cause no transition of the signal, the receiver cannot
adjust its clock to maintain proper synchronised reception.
To eliminate the possibility of such a pathological case, when
a preset number of transitionless bits have been transmitted,
a bit which does cause a transition is "stuffed" (transmitted)
by the sender. The receiver follows the same protocol and
removes the stuffed bit after the specified number of
transitionless bits, but can use the stuffed bit to recover
the sender's clock.
The advantage of bit stuffing is that only a bit (not a
byte) is inserted in the data stream, and that only when the
content of the data stream fails to provide a timing signal to
the receiver. Thus very nearly 100% of the bits transported
are useful data. In contrast, asynchronous transmission of
data "throws away" a start bit and one or more stop bits for
each data byte sent.
(1996-04-23)
Nearby terms:
bits per pixel « bits per second « bit string « bit stuffing » bit twiddling » bitty box » bitwise
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