| slovo | definícia |
random
(mass) | random
- nahodilý, náhodný |
random
(encz) | random,náhoda n: holdsun |
random
(encz) | random,nahodilý adj: |
random
(encz) | random,náhodný adj: Pavel Machek; Giza |
Random
(gcide) | Random \Ran"dom\, a.
1. Going at random or by chance; done or made at hazard, or
without settled direction, aim, or purpose; hazarded
without previous calculation; left to chance; haphazard;
as, a random guess.
[1913 Webster]
Some random truths he can impart. --Wordsworth.
[1913 Webster]
So sharp a spur to the lazy, and so strong a bridle
to the random. --H. Spencer.
[1913 Webster]
2. (Statistics) Of, pertaining to, or resulting from a
process of selection from a starting set of items, in
which the probability of selecting any one object in the
starting set is equal to the probability of selecting any
other.
[PJC]
3. (Construction) of unequal size or shape; made from
components of unequal size or shape.
[PJC]
at random in a manner so that all possible results have an
equal probability of occurrence; for processes, each
possible result is counted separately although the same
type of result may occur more than once .
Random courses (Masonry), courses of stone of unequal
thickness.
Random shot, a shot not directed or aimed toward any
particular object, or a shot with the muzzle of the gun
much elevated.
Random work (Masonry), stonework consisting of stones of
unequal sizes fitted together, but not in courses nor
always with flat beds.
[1913 Webster] |
Random
(gcide) | Random \Ran"dom\ (r[a^]n"d[u^]m), n. [OE. randon, OF. randon
force, violence, rapidity, [`a] randon, de randon, violently,
suddenly, rapidly, prob. of German origin; cf. G. rand edge,
border, OHG. rant shield, edge of a shield, akin to E. rand,
n. See Rand, n.]
1. Force; violence. [Obs.]
[1913 Webster]
For courageously the two kings newly fought with
great random and force. --E. Hall.
[1913 Webster]
2. A roving motion; course without definite direction; want
of direction, rule, or method; hazard; chance; -- commonly
used in the phrase at random, that is, without a settled
point of direction; at hazard.
[1913 Webster]
Counsels, when they fly
At random, sometimes hit most happily. --Herrick.
[1913 Webster]
O, many a shaft, at random sent,
Finds mark the archer little meant! --Sir W.
Scott.
[1913 Webster]
3. Distance to which a missile is cast; range; reach; as, the
random of a rifle ball. --Sir K. Digby.
[1913 Webster]
4. (Mining) The direction of a rake-vein. --Raymond.
[1913 Webster] |
random
(wn) | random
adj 1: lacking any definite plan or order or purpose; governed
by or depending on chance; "a random choice"; "bombs fell
at random"; "random movements" [ant: nonrandom] |
random
(foldoc) | random
1. Unpredictable (closest to mathematical definition); weird.
"The system's been behaving pretty randomly."
2. Assorted; undistinguished. "Who was at the conference?"
"Just a bunch of random business types."
3. (pejorative) Frivolous; unproductive; undirected. "He's
just a random loser."
4. Incoherent or inelegant; poorly chosen; not well organised.
"The program has a random set of misfeatures." "That's a
random name for that function." "Well, all the names were
chosen pretty randomly."
5. In no particular order, though deterministic. "The I/O
channels are in a pool, and when a file is opened one is
chosen randomly."
6. Arbitrary. "It generates a random name for the scratch
file."
7. Gratuitously wrong, i.e. poorly done and for no good
apparent reason. For example, a program that handles file
name defaulting in a particularly useless way, or an assembler
routine that could easily have been coded using only three
registers, but redundantly uses seven for values with
non-overlapping lifetimes, so that no one else can invoke it
without first saving four extra registers. What randomness!
8. A random hacker; used particularly of high-school students
who soak up computer time and generally get in the way.
9. Anyone who is not a hacker (or, sometimes, anyone not
known to the hacker speaking). "I went to the talk, but the
audience was full of randoms asking bogus questions".
10. (occasional MIT usage) One who lives at Random Hall. See
also J. Random, some random X.
[Jargon File]
(1995-12-05)
|
random
(jargon) | random
adj.
1. Unpredictable (closest to mathematical definition); weird. “The system's
been behaving pretty randomly.”
2. Assorted; undistinguished. “Who was at the conference?” “Just a bunch of
random business types.”
3. (pejorative) Frivolous; unproductive; undirected. “He's just a random
loser.”
4. Incoherent or inelegant; poorly chosen; not well organized. “The program
has a random set of misfeatures.” “That's a random name for that function.”
“Well, all the names were chosen pretty randomly.”
5. In no particular order, though deterministic. “The I/O channels are in a
pool, and when a file is opened one is chosen randomly.”
6. Arbitrary. “It generates a random name for the scratch file.”
7. Gratuitously wrong, i.e., poorly done and for no good apparent reason.
For example, a program that handles file name defaulting in a particularly
useless way, or an assembler routine that could easily have been coded
using only three registers, but redundantly uses seven for values with
non-overlapping lifetimes, so that no one else can invoke it without first
saving four extra registers. What randomness!
8. n. A random hacker; used particularly of high-school students who soak
up computer time and generally get in the way.
9. n. Anyone who is not a hacker (or, sometimes, anyone not known to the
hacker speaking); the noun form of sense 2. “I went to the talk, but the
audience was full of randoms asking bogus questions”.
10. n. (occasional MIT usage) One who lives at Random Hall. See also {J.
Random}, some random X.
11. [UK] Conversationally, a non sequitur or something similarly
out-of-the-blue. As in: “Stop being so random!” This sense equates to
‘hatstand’, taken from the Viz comic character “Roger Irrelevant - He's
completely Hatstand.”
|
| | podobné slovo | definícia |
random
(mass) | random
- nahodilý, náhodný |
randomization
(mass) | randomization
- náhodnosť |
randomly
(mass) | randomly
- náhodne |
at random
(encz) | at random,nazdařbůh Rostislav Svoboda |
nonrandom
(encz) | nonrandom,nenáhodný |
pseudorandom
(encz) | pseudorandom,pseudonáhodný adj: [it.] jk |
random
(encz) | random,náhoda n: holdsunrandom,nahodilý adj: random,náhodný adj: Pavel Machek; Giza |
random acces memory
(encz) | random acces memory,RAM pamět s náhodným přístupem |
random access memory
(encz) | random access memory, n: |
random bidding model
(encz) | random bidding model,model náhodné licitace [eko.] RNDr. Pavel Piskač |
random memory
(encz) | random memory, n: |
random number generator
(encz) | random number generator, n: |
random sample
(encz) | random sample, n: |
random sampling
(encz) | random sampling, n: |
random utility model rum.
(encz) | Random Utility Model RUM.,model náhodného prospěchu [eko.] RNDr. Pavel
Piskač |
random variable
(encz) | random variable,náhodná proměnná n: [mat.] Zdeněk Brožrandom variable,náhodná veličina n: [mat.] Stanislav Horáček |
random walk
(encz) | random walk, n: |
random-access
(encz) | random-access,náhodný přístup n: web |
random-access memory
(encz) | random-access memory,paměť možností náhodného přístupu - RAM n:
[it.] web |
randomisation
(encz) | randomisation,náhodné rozdělování n: Zdeněk Brož |
randomise
(encz) | randomise,generovat náhodná čísla n: Zdeněk Brožrandomise,náhodně rozmístit Zdeněk Brož |
randomised
(encz) | randomised,náhodně rozmístěný Zdeněk Brož |
randomising
(encz) | randomising, |
randomization
(encz) | randomization, |
randomize
(encz) | randomize,náhodně rozdělit Zdeněk Brožrandomize,tvořit náhodná čísla n: Zdeněk Brož |
randomized
(encz) | randomized,náhodně rozdělil Zdeněk Brož |
randomizing
(encz) | randomizing, |
randomly
(encz) | randomly,náhodně adv: web |
randomness
(encz) | randomness,náhodnost n: Zdeněk Brož |
random act of kindness
(czen) | Random Act of Kindness,RAK[zkr.] |
at random
(gcide) | Random \Ran"dom\, a.
1. Going at random or by chance; done or made at hazard, or
without settled direction, aim, or purpose; hazarded
without previous calculation; left to chance; haphazard;
as, a random guess.
[1913 Webster]
Some random truths he can impart. --Wordsworth.
[1913 Webster]
So sharp a spur to the lazy, and so strong a bridle
to the random. --H. Spencer.
[1913 Webster]
2. (Statistics) Of, pertaining to, or resulting from a
process of selection from a starting set of items, in
which the probability of selecting any one object in the
starting set is equal to the probability of selecting any
other.
[PJC]
3. (Construction) of unequal size or shape; made from
components of unequal size or shape.
[PJC]
at random in a manner so that all possible results have an
equal probability of occurrence; for processes, each
possible result is counted separately although the same
type of result may occur more than once .
Random courses (Masonry), courses of stone of unequal
thickness.
Random shot, a shot not directed or aimed toward any
particular object, or a shot with the muzzle of the gun
much elevated.
Random work (Masonry), stonework consisting of stones of
unequal sizes fitted together, but not in courses nor
always with flat beds.
[1913 Webster] |
random access memory
(gcide) | main memory \main memory\ n. (Computers)
The memory in a computer that holds programs and data for
rapid access during execution of a program; it usually hold
the largest quantity of rapid-access storage in a computer;
-- also called RAM (random access memory. It is
contrasted to ROM, disk data storage, cache,
registers and other forms of data storage.
[PJC] |
Random courses
(gcide) | Random \Ran"dom\, a.
1. Going at random or by chance; done or made at hazard, or
without settled direction, aim, or purpose; hazarded
without previous calculation; left to chance; haphazard;
as, a random guess.
[1913 Webster]
Some random truths he can impart. --Wordsworth.
[1913 Webster]
So sharp a spur to the lazy, and so strong a bridle
to the random. --H. Spencer.
[1913 Webster]
2. (Statistics) Of, pertaining to, or resulting from a
process of selection from a starting set of items, in
which the probability of selecting any one object in the
starting set is equal to the probability of selecting any
other.
[PJC]
3. (Construction) of unequal size or shape; made from
components of unequal size or shape.
[PJC]
at random in a manner so that all possible results have an
equal probability of occurrence; for processes, each
possible result is counted separately although the same
type of result may occur more than once .
Random courses (Masonry), courses of stone of unequal
thickness.
Random shot, a shot not directed or aimed toward any
particular object, or a shot with the muzzle of the gun
much elevated.
Random work (Masonry), stonework consisting of stones of
unequal sizes fitted together, but not in courses nor
always with flat beds.
[1913 Webster] |
Random shot
(gcide) | Random \Ran"dom\, a.
1. Going at random or by chance; done or made at hazard, or
without settled direction, aim, or purpose; hazarded
without previous calculation; left to chance; haphazard;
as, a random guess.
[1913 Webster]
Some random truths he can impart. --Wordsworth.
[1913 Webster]
So sharp a spur to the lazy, and so strong a bridle
to the random. --H. Spencer.
[1913 Webster]
2. (Statistics) Of, pertaining to, or resulting from a
process of selection from a starting set of items, in
which the probability of selecting any one object in the
starting set is equal to the probability of selecting any
other.
[PJC]
3. (Construction) of unequal size or shape; made from
components of unequal size or shape.
[PJC]
at random in a manner so that all possible results have an
equal probability of occurrence; for processes, each
possible result is counted separately although the same
type of result may occur more than once .
Random courses (Masonry), courses of stone of unequal
thickness.
Random shot, a shot not directed or aimed toward any
particular object, or a shot with the muzzle of the gun
much elevated.
Random work (Masonry), stonework consisting of stones of
unequal sizes fitted together, but not in courses nor
always with flat beds.
[1913 Webster] |
Random work
(gcide) | Random \Ran"dom\, a.
1. Going at random or by chance; done or made at hazard, or
without settled direction, aim, or purpose; hazarded
without previous calculation; left to chance; haphazard;
as, a random guess.
[1913 Webster]
Some random truths he can impart. --Wordsworth.
[1913 Webster]
So sharp a spur to the lazy, and so strong a bridle
to the random. --H. Spencer.
[1913 Webster]
2. (Statistics) Of, pertaining to, or resulting from a
process of selection from a starting set of items, in
which the probability of selecting any one object in the
starting set is equal to the probability of selecting any
other.
[PJC]
3. (Construction) of unequal size or shape; made from
components of unequal size or shape.
[PJC]
at random in a manner so that all possible results have an
equal probability of occurrence; for processes, each
possible result is counted separately although the same
type of result may occur more than once .
Random courses (Masonry), courses of stone of unequal
thickness.
Random shot, a shot not directed or aimed toward any
particular object, or a shot with the muzzle of the gun
much elevated.
Random work (Masonry), stonework consisting of stones of
unequal sizes fitted together, but not in courses nor
always with flat beds.
[1913 Webster] |
Randomize
(gcide) | Randomize \Ran"dom*ize\, v. t.
To arrange or rearrange so that there is no predetermined
order; to make random; to select by a random process; to
assign (members of a group) into subgroups by a random
process.
Syn: make random.
[PJC] |
Randomly
(gcide) | Randomly \Ran"dom*ly\ (r[a^]n"d[u^]m*l[y^]), adv.
In a random manner.
[1913 Webster] |
at random
(wn) | at random
adv 1: in a random manner; "the houses were randomly scattered";
"bullets were fired into the crowd at random" [syn:
randomly, indiscriminately, haphazardly, {willy-
nilly}, arbitrarily, at random, every which way] |
nonrandom
(wn) | nonrandom
adj 1: not random [ant: random] |
random
(wn) | random
adj 1: lacking any definite plan or order or purpose; governed
by or depending on chance; "a random choice"; "bombs fell
at random"; "random movements" [ant: nonrandom] |
random access memory
(wn) | random access memory
n 1: the most common computer memory which can be used by
programs to perform necessary tasks while the computer is
on; an integrated circuit memory chip allows information to
be stored or accessed in any order and all storage
locations are equally accessible [syn: {random-access
memory}, random access memory, random memory, RAM,
read/write memory] |
random memory
(wn) | random memory
n 1: the most common computer memory which can be used by
programs to perform necessary tasks while the computer is
on; an integrated circuit memory chip allows information to
be stored or accessed in any order and all storage
locations are equally accessible [syn: {random-access
memory}, random access memory, random memory, RAM,
read/write memory] |
random number generator
(wn) | random number generator
n 1: a routine designed to yield a random number |
random sample
(wn) | random sample
n 1: a sample in which every element in the population has an
equal chance of being selected
2: a sample grabbed at random |
random sampling
(wn) | random sampling
n 1: the selection of a random sample; each element of the
population has an equal chance of been selected |
random variable
(wn) | random variable
n 1: a variable quantity that is random [syn: random variable,
variate, variant, stochastic variable, {chance
variable}] |
random walk
(wn) | random walk
n 1: a stochastic process consisting of a sequence of changes
each of whose characteristics (as magnitude or direction)
is determined by chance |
random-access memory
(wn) | random-access memory
n 1: the most common computer memory which can be used by
programs to perform necessary tasks while the computer is
on; an integrated circuit memory chip allows information to
be stored or accessed in any order and all storage
locations are equally accessible [syn: {random-access
memory}, random access memory, random memory, RAM,
read/write memory] |
randomisation
(wn) | randomisation
n 1: a deliberately haphazard arrangement of observations so as
to simulate chance [syn: randomization, randomisation] |
randomise
(wn) | randomise
v 1: arrange in random order; "Randomize the order of the
numbers" [syn: randomize, randomise] |
randomised
(wn) | randomised
adj 1: set up or distributed in a deliberately random way [syn:
randomized, randomised] |
randomization
(wn) | randomization
n 1: a deliberately haphazard arrangement of observations so as
to simulate chance [syn: randomization, randomisation] |
randomize
(wn) | randomize
v 1: arrange in random order; "Randomize the order of the
numbers" [syn: randomize, randomise] |
randomized
(wn) | randomized
adj 1: set up or distributed in a deliberately random way [syn:
randomized, randomised] |
randomly
(wn) | randomly
adv 1: in a random manner; "the houses were randomly scattered";
"bullets were fired into the crowd at random" [syn:
randomly, indiscriminately, haphazardly, {willy-
nilly}, arbitrarily, at random, every which way] |
randomness
(wn) | randomness
n 1: (thermodynamics) a thermodynamic quantity representing the
amount of energy in a system that is no longer available
for doing mechanical work; "entropy increases as matter and
energy in the universe degrade to an ultimate state of
inert uniformity" [syn: randomness, entropy, S]
2: the quality of lacking any predictable order or plan [syn:
randomness, haphazardness, stochasticity, noise] |
burst static random access memory
(foldoc) | Burst Static Random Access Memory
BSRAM
(BSRAM) A kind of SRAM used primarily for external
Level 2 cache memory.
[How does it work?]
(1998-02-24)
|
digital versatile disk random access memory
(foldoc) | Digital Versatile Disk Random Access Memory
DVD-RAM
(DVD-RAM) Rewritable DVD media that is recordable
on both sides, giving up to 9.6GB of storage. A drive can
record to disk and read from it at the same time, so the term
full duplex is often used. There are two general types of
media: traditional discrete disk in DVD or Jewel case, and one
in a permanent case like a large floppy; the disk remains in
the case, and the case goes into the drive. The former can
sometimes be read by regular DVD drives; the latter obviously
cannot.
{Technical details, somewhat dated, at burnworld.com
(http://burnworld.com/dvd/primer/dvdram.htm)}.
(2005-01-26)
|
double data rate random access memory
(foldoc) | Double Data Rate Random Access Memory
DDR
DDR-RAM
DDR-SDRAM
Double Data Rate Synchronous Random Access Memory
(DDR-RAM, DDR-SDRAM ...Synchronous...) RAM that
transfers data on both 0-1 and 1-0 clock transitions,
theoretically yielding twice the data transfer rate of normal
RAM or SDRAM.
{DDR-RAM Article
(http://pcreview.co.uk/Article.php?aid=9)}.
{DDR-SDRAM Article
(http://www4.tomshardware.com/mainboard/00q4/001030/)}.
(2001-05-24)
|
double data rate synchronous random access memory
(foldoc) | Double Data Rate Random Access Memory
DDR
DDR-RAM
DDR-SDRAM
Double Data Rate Synchronous Random Access Memory
(DDR-RAM, DDR-SDRAM ...Synchronous...) RAM that
transfers data on both 0-1 and 1-0 clock transitions,
theoretically yielding twice the data transfer rate of normal
RAM or SDRAM.
{DDR-RAM Article
(http://pcreview.co.uk/Article.php?aid=9)}.
{DDR-SDRAM Article
(http://www4.tomshardware.com/mainboard/00q4/001030/)}.
(2001-05-24)
|
dynamic random-access memory
(foldoc) | dynamic random-access memory
DRAM
dynamic RAM
(DRAM) A type of semiconductor memory in which the
information is stored in capacitors on a MOS {integrated
circuit}. Typically each bit is stored as an amount of
electrical charge in a storage cell consisting of a capacitor
and a transistor. Due to leakage the capacitor discharges
gradually and the memory cell loses the information.
Therefore, to preserve the information, the memory has to be
refreshed periodically. Despite this inconvenience, the DRAM
is a very popular memory technology because of its high
density and consequent low price.
The first commercially available DRAM chip was the {Intel
1103}, introduced in 1970.
Early DRAM chips, containing up to a 16k x 1 (16384 locations
of one bit each), needed 3 supply voltages (+5V, -5V and
+12V). Beginning with the 64 kilobit chips, charge pumps
were included on-chip to create the necessary supply voltages
out of a single +5V supply. This was necessary to fit the
device into a 16-pin DIL package, which was the preferred
package at the time, and also made them easier to use.
To reduce the pin count, thereby helping miniaturisation,
DRAMs generally had a single data line which meant that a
computer with an N bit wide data bus needed a "bank" of (at
least) N DRAM chips. In a bank, the address and control
signals of all chips were common and the data line of each
chip was connected to one of the data bus lines.
Beginning with the 256 kilobit DRAM, a tendency toward
surface mount packaging arose and DRAMs with more than one
data line appeared (e.g. 64k x 4), reducing the number of
chips per bank. This trend has continued and DRAM chips with
up to 36 data lines are available today. Furthermore,
together with surface mount packages, memory manufacturers
began to offer memory modules, where a bank of memory chips
was preassembled on a little printed circuit board (SIP =
Single Inline Pin Module, SIMM = Single Inline Memory Module,
DIMM = Dual Inline Memory Module). Today, this is the
preferred way to buy memory for workstations and {personal
computers}.
DRAM bit cells are arranged on a chip in a grid of rows and
columns where the number of rows and columns are usually a
power of two. Often, but not always, the number of rows and
columns is the same. A one megabit device would then have
1024 x 1024 memory cells. A single memory cell can be
selected by a 10-bit row address and a 10-bit column address.
To access a memory cell, one entire row of cells is selected
and its contents are transferred into an on-chip buffer. This
discharges the storage capacitors in the bit cells. The
desired bits are then read or written in the buffer. The
(possibly altered) information is finally written back into
the selected row, thereby refreshing all bits (recharging the
capacitors) in the row.
To prevent data loss, all bit cells in the memory need to be
refreshed periodically. This can be done by reading all rows
in regular intervals. Most DRAMs since 1970 have been
specified such that one of the rows needs to be refreshed at
least every 15.625 microseconds. For a device with 1024 rows,
a complete refresh of all rows would then take up to 16 ms; in
other words, each cell is guaranteed to hold the data for 16
ms without refresh. Devices with more rows have accordingly
longer retention times.
Many varieties of DRAM exist today. They differ in the way
they are interfaced to the system - the structure of the
memory cell itself is essentially the same.
"Traditional" DRAMs have multiplexed address lines and
separate data inputs and outputs. There are three control
signals: RAS\ (row address strobe), CAS\ (column address
strobe), and WE\ (write enable) (the backslash indicates an
active low signal). Memory access procedes as follows:
1. The control signals initially all being inactive (high), a
memory cycle is started with the row address applied to the
address inputs and a falling edge of RAS\ . This latches the
row address and "opens" the row, transferring the data in the
row to the buffer. The row address can then be removed from
the address inputs since it is latched on-chip. 2. With RAS\
still active, the column address is applied to the address
pins and CAS\ is made active as well. This selects the
desired bit or bits in the row which subsequently appear at
the data output(s). By additionally activating WE\ the data
applied to the data inputs can be written into the selected
location in the buffer. 3. Deactivating CAS\ disables the
data input and output again. 4. Deactivating RAS\ causes the
data in the buffer to be written back into the memory array.
Certain timing rules must be obeyed to guarantee reliable
operation. 1. RAS\ must remain inactivate for a while before
the next memory cycle is started to provide sufficient time
for the storage capacitors to charge (Precharge Time). 2. It
takes some time from the falling edge of the RAS\ or CAS\
signals until the data appears at the data output. This is
specified as the Row Access Time and the Column Access Time.
Current DRAM's have Row Access Times of 50-100 ns and Column
Access Times of 15-40 ns. Speed grades usually refer to the
former, more important figure.
Note that the Memory Cycle Time, which is the minimum time
from the beginning of one access to the beginning of the next,
is longer than the Row Access Time (because of the Precharge
Time).
Multiplexing the address pins saves pins on the chip, but
usually requires additional logic in the system to properly
generate the address and control signals, not to mention
further logic for refresh. Therefore, DRAM chips are usually
preferred when (because of the required memory size) the
additional cost for the control logic is outweighed by the
lower price.
Based on these principles, chip designers have developed many
varieties to improve performance or ease system integration of
DRAMs:
PSRAMs (Pseudo Static Random Access Memory) are essentially
DRAMs with a built-in address multiplexor and refresh
controller. This saves some system logic and makes the device
look like a normal SRAM. This has been popular as a lower
cost alternative for SRAM in embedded systems. It is not a
complete SRAM substitute because it is sometimes busy when
doing self-refresh, which can be tedious.
Nibble Mode DRAM can supply four successive bits on one data
line by clocking the CAS\ line.
Page Mode DRAM is a standard DRAM where any number of
accesses to the currently open row can be made while the RAS
signal is kept active.
Static Column DRAM is similar to Page Mode DRAM, but to access
different bits in the open row, only the column address needs
to be changed while the CAS\ signal stays active. The row
buffer essentially behaves like SRAM.
Extended Data Out DRAM (EDO DRAM) can continue to output
data from one address while setting up a new address, for use
in pipelined systems.
DRAM used for Video RAM (VRAM) has an additional long
shift register that can be loaded from the row buffer. The
shift register can be regarded as a second interface to the
memory that can be operated in parallel to the normal
interface. This is especially useful in frame buffers for
CRT displays. These frame buffers generate a serial data
stream that is sent to the CRT to modulate the electron beam.
By using the shift register in the VRAM to generate this
stream, the memory is available to the computer through the
normal interface most of the time for updating the display
data, thereby speeding up display data manipulations.
SDRAM (Synchronous DRAM) adds a separate clock signal to the
control signals. It allows more complex state machines on
the chip and high speed "burst" accesses that clock a series
of successive bits out (similar to the nibble mode).
CDRAM (Cached DRAM) adds a separate static RAM array used for
caching. It essentially combines main memory and cache
memory in a single chip. The cache memory controller needs to
be added externally.
RDRAM (Rambus DRAM) changes the system interface of DRAM
completely. A byte-wide bus is used for address, data and
command transfers. The bus operates at very high speed: 500
million transfers per second. The chip operates synchronously
with a 250MHz clock. Data is transferred at both rising and
falling edges of the clock. A system with signals at such
frequencies must be very carefully designed, and the signals
on the Rambus Channel use nonstandard signal levels, making it
incompatible with standard system logic. These disadvantages
are compensated by a very fast data transfer, especially for
burst accesses to a block of successive locations.
A number of different refresh modes can be included in some of
the above device varieties:
RAS\ only refresh: a row is refreshed by an ordinary read
access without asserting CAS\. The data output remains
disabled.
CAS\ before RAS\ refresh: the device has a built-in counter
for the refresh row address. By activating CAS\ before
activating RAS\, this counter is selected to supply the row
address instead of the address inputs.
Self-Refresh: The device is able to generate refresh cycles
internally. No external control signal transitions other than
those for bringing the device into self-refresh mode are
needed to maintain data integrity.
(1996-07-11)
|
enhanced dynamic random access memory
(foldoc) | Enhanced Dynamic Random Access Memory
EDRAM
(EDRAM)
(http://ruralnet.net/~prairie).
[Summary?]
(1995-11-23)
|
extended data out dynamic random access memory
(foldoc) | Extended Data Out Dynamic Random Access Memory
EDO DRAM
EDO memory
EDO RAM
Extended Data Out Random Access Memory
(EDO DRAM, EDO RAM) A type of DRAM designed to
access nearby memory locations faster than FPM DRAM.
Extended Data Out DRAM (EDO-DRAM) allows the data outputs to
be kept active after the CAS\ signal goes inactive, using an
additional signal OE\ to control the data outputs. This can
be used in pipelined systems for overlapping accesses where
the next cycle is started before the data from the last cycle
is removed from the bus.
EDO DRAM is primarily used with Intel's Pentium processors
since with slower processors there is no significant
performance gain. To make use of the advanced features of EDO
an appropriate chipset, such as Triton, must be used. In
early 1995, EDO DRAM was available for computers from
Micron, Gateway 2000, and Intel Corporation; since then
other manufactures followed suit.
Note that in comparison to Burst EDO EDO is sometimes
referred to as "Standard EDO".
(1996-06-25)
|
extended data out random access memory
(foldoc) | Extended Data Out Dynamic Random Access Memory
EDO DRAM
EDO memory
EDO RAM
Extended Data Out Random Access Memory
(EDO DRAM, EDO RAM) A type of DRAM designed to
access nearby memory locations faster than FPM DRAM.
Extended Data Out DRAM (EDO-DRAM) allows the data outputs to
be kept active after the CAS\ signal goes inactive, using an
additional signal OE\ to control the data outputs. This can
be used in pipelined systems for overlapping accesses where
the next cycle is started before the data from the last cycle
is removed from the bus.
EDO DRAM is primarily used with Intel's Pentium processors
since with slower processors there is no significant
performance gain. To make use of the advanced features of EDO
an appropriate chipset, such as Triton, must be used. In
early 1995, EDO DRAM was available for computers from
Micron, Gateway 2000, and Intel Corporation; since then
other manufactures followed suit.
Note that in comparison to Burst EDO EDO is sometimes
referred to as "Standard EDO".
(1996-06-25)
|
fast page mode dynamic random access memory
(foldoc) | Fast Page Mode Dynamic Random Access Memory
FPM
FPM DRAM
Is this the same as {Page Mode Dynamic
Random Access Memory}?
(1996-10-06)
|
ferroelectric random access memory
(foldoc) | Ferroelectric Random Access Memory
Ferroelectric RAM
FRAM
(FRAM) A type of non-volatile read/write {random
access} semiconductor memory. FRAM combines the advantages
of SRAM - writing is roughly as fast as reading, and EPROM
- non-volatility and in-circuit programmability. Current (Feb
1997) disadvantages are high cost and low density, but that
may change in the future. Density is currently at most 32KB
on a chip, compared with 512KB for SRAM, 1MB for EPROM and 8MB
for DRAM.
A ferroelectric memory cell consists of a ferroelectric
capacitor and a MOS transistor. Its construction is
similar to the storage cell of a DRAM. The difference is in
the dielectric properties of the material between the
capacitor's electrodes. This material has a high dielectric
constant and can be polarized by an electric field. The
polarisation remains until it gets reversed by an opposite
electrical field. This makes the memory non-volatile. Note
that ferroelectric material, despite its name, does not
necessarily contain iron. The most well-known ferroelectric
substance is BaTiO3, which does not contain iron.
Data is read by applying an electric field to the capacitor.
If this switches the cell into the opposite state (flipping
over the electrical dipoles in the ferroelectric material)
then more charge is moved than if the cell was not flipped.
This can be detected and amplified by sense amplifiers.
Reading destroys the contents of a cell which must therefore
be written back after a read. This is similar to the
precharge operation in DRAM, though it only needs to be done
after a read rather than periodically as with DRAM refresh.
In fact it is most like the operation of {ferrite core
memory}.
FRAM has similar applications to EEPROM, but can be written
much faster. The simplicity of the memory cell promises high
density devices which can compete with DRAM.
RAMTRON is the company behind FRAM.
(1997-02-17)
|
j. random
(foldoc) | J. Random
/J rand'm/ (Generalised from J. Random Hacker)
Arbitrary; ordinary; any one; any old. "J. Random" is often
prefixed to a noun to make a name out of it. It means roughly
"some particular" or "any specific one". "Would you let
J. Random Loser marry your daughter?" The most common uses
are "J. Random Hacker", "J. Random Loser", and "J. Random
Nerd" ("Should J. Random Loser be allowed to gun down other
people?"), but it can be used simply as an elaborate version
of random in any sense.
[Jargon File]
|
j. random hacker
(foldoc) | J. Random Hacker
/J rand'm hak'r/ MIT jargon for a mythical figure;
the archetypal hacker nerd.
This may originally have been inspired by "J. Fred Muggs", a
show-biz chimpanzee whose name was a household word back in
the early days of TMRC, and was probably influenced by
J. Presper Eckert (one of the co-inventors of the electronic
computer).
See random, Suzie COBOL.
(1996-10-16)
|
non-volatile random access memory
(foldoc) | Non-Volatile Random Access Memory
NVRAM
(NVRAM) Static random-access memory which is made
into non-volatile storage either by having a battery
permanently connected or by saving its contents to EEPROM
before turning the power off and reloading it when power is
restored.
(1995-04-22)
|
page mode dynamic random access memory
(foldoc) | Page Mode Dynamic Random Access Memory
Page Mode DRAM
A technique used to support faster
sequential access to DRAM by allowing any number of accesses
to the currently open row to be made after supplying the {row
address} just once.
The RAS signal is kept active, and with each falling edge
of the CAS\ signal a new column address can be supplied
and the corresponding bits can be accessed. This is faster
than a full RAS-CAS cycle because only the shorter Column
Access Time needs to be obeyed.
Note that strictly speaking such a DRAM is not a true {random
access memory} since accesses to the open row are faster than
to other locations.
EDO RAM is replacing Page Mode DRAM in many new
microcomputers.
[Is "Fast Page Mode" the same as "Page Mode"?]
(1996-10-06)
|
parallel random-access machine
(foldoc) | parallel random-access machine
(PRAM) An idealised parallel processor consisting
of P processors, unbounded shared memory, and a common
clock. Each processor is a random-access machine (RAM)
consisting of R registers, a program counter, and a
read-only signature register. Each RAM has an identical
program, but the RAMs can branch to different parts of the
program. The RAMs execute the program synchronously one
instruction in one clock cycle.
See also pm2.
(1997-06-04)
|
pseudorandom number
(foldoc) | pseudorandom number
random number
One of a sequence of numbers generated by some
algorithm so as to have an even distribution over some range
of values and minimal correlation between successive
values.
Pseudorandom numbers are used in simulation and
encryption. They are pseudorandom not random because the
sequence eventually repeats exactly and is entirely determined
by the initial conditions.
One of the simplest algorithms is
x[i+1] = (a * x[i] + c) mod m
but this repeats after at most m numbers and successive
numbers are closely related. Better algorithms generally use
more previous numbers to calculate the next number.
(http://random.mat.sbg.ac.at/).
(2007-06-29)
|
random
(foldoc) | random
1. Unpredictable (closest to mathematical definition); weird.
"The system's been behaving pretty randomly."
2. Assorted; undistinguished. "Who was at the conference?"
"Just a bunch of random business types."
3. (pejorative) Frivolous; unproductive; undirected. "He's
just a random loser."
4. Incoherent or inelegant; poorly chosen; not well organised.
"The program has a random set of misfeatures." "That's a
random name for that function." "Well, all the names were
chosen pretty randomly."
5. In no particular order, though deterministic. "The I/O
channels are in a pool, and when a file is opened one is
chosen randomly."
6. Arbitrary. "It generates a random name for the scratch
file."
7. Gratuitously wrong, i.e. poorly done and for no good
apparent reason. For example, a program that handles file
name defaulting in a particularly useless way, or an assembler
routine that could easily have been coded using only three
registers, but redundantly uses seven for values with
non-overlapping lifetimes, so that no one else can invoke it
without first saving four extra registers. What randomness!
8. A random hacker; used particularly of high-school students
who soak up computer time and generally get in the way.
9. Anyone who is not a hacker (or, sometimes, anyone not
known to the hacker speaking). "I went to the talk, but the
audience was full of randoms asking bogus questions".
10. (occasional MIT usage) One who lives at Random Hall. See
also J. Random, some random X.
[Jargon File]
(1995-12-05)
|
random access memory digital-to-analog converter
(foldoc) | Random Access Memory Digital-to-Analog Converter
RAMDAC
(RAMDAC) A combination of three fast DACs with a
small SRAM used in graphics display adapters to store the
colour palette and to generate the analog signals to drive a
colour monitor. The logical colour number from the display
memory is fed into the address inputs of the SRAM to select a
palette entry to appear on the output of the SRAM. This entry
is composed of three separate values corresponding to the
three components (red, green, and blue) of the desired
physical colour. Each component value is fed to a separate
DAC, whose analog output goes to the monitor, and ultimately
to one of its three electron guns (or equivalent in
non-CRT displays).
DAC word lengths range usually from 6 to 10 bits. The SRAM's
wordlength is three times the DAC's word length. The SRAM
acts as a colour lookup table. It usually has 256 entries
(and thus an 8-bit address). If the DAC's word length is also
8 bits, we have a 256 x 24-bit SRAM which allows a selection
of 256 out of 16777216 possible colours for the display. The
contents of the SRAM can be changed while the display is not
active (during display blanking times). The SRAM can
usually be bypassed and the DACs can be fed directly by
display data (for true colour modes).
(1996-03-24)
|
random number
(foldoc) | pseudorandom number
random number
One of a sequence of numbers generated by some
algorithm so as to have an even distribution over some range
of values and minimal correlation between successive
values.
Pseudorandom numbers are used in simulation and
encryption. They are pseudorandom not random because the
sequence eventually repeats exactly and is entirely determined
by the initial conditions.
One of the simplest algorithms is
x[i+1] = (a * x[i] + c) mod m
but this repeats after at most m numbers and successive
numbers are closely related. Better algorithms generally use
more previous numbers to calculate the next number.
(http://random.mat.sbg.ac.at/).
(2007-06-29)
|
random testing
(foldoc) | random testing
A black-box testing approach in which
software is tested by choosing an arbitrary subset of all
possible input values. Random testing helps to avoid the
problem of only testing what you know will work.
(2001-04-30)
|
|