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R/W
- Refer to read/write.
Radiation
- The emission of
energy as radio waves or particles. Radiation is absorbed by the body,
sometimes causing physical problems ranging from headaches to cancer. All
monitors emit radiation, but color monitors send out more than monochrome
monitors. Experts disagree about whether the rotation from a computer is
significant health risk. However the amount of radiation that is absorbed
from a computer is less than what an average user is exposed to by
household appliances.
Radio
button - Round circle
representing choices in a common option list form in a graphical user
interface.
Radio
frequency (RF) - The
range of frequencies from 10 kilohertz to 3,000 gigahertz on the
electromagnetic spectrum between light and sound.
Radio
frequency shielding (RF shielding) - Material designed to keep radio frequency (RF) electromagnetic radiation
confined inside or sealed out of a device.
Radix
- The base value of a
number system. For example, in the decimal (base 10) system, the radix is
10, while in the binary system (base-2) the radix is 2.
Rag
- To format a page
leaving lines of text uneven along the side of a page Generally, the left
side of text is justified, and the right is ragged.
Ragged
left/right - Term that
explains which side of a body of text is ragged. Ragged left means the
left side is ragged while the right is even or vise versa.
RAID
- Refer to Redundant
Array of Inexpensive Disks.
RAM
- Refer to
Random-Access memory.
RAM
cache - Cache made of
high speed static RAM (SRAM) linked directly to the CPU. RAM caches are
used for keeping a copy of the most recently and most frequently accessed
data in memory so the information is more quickly accessible. Also Called
a memory Cache or processor cache.
RAM
card - An add-in board
used to add RAM to a system. RAM cards are inserted into slots on the
motherboard.
RAM
cartridge - Refer to
memory cartridge.
RAM
chip - A chip that
contains RAM storage.
Ram
digital-to-analog converter (RAMDAC) - Pronounced RAM Dack. A video adapter chip that changes the digital data
of a pixel in memory into the analog signal for display on the monitor.
RAM
disk - Simulated disk
drive, or a part of memory that acts as a logical disk drive, whose
contents are actually stored in RAM memory. A RAM disk is very fast
because an electronic rather than a physical storage device will be
accessed, thus creating less work and increasing the speed. To create a
Simulated disk drive via DOS you can use the SUBST
command.
RAM
drive - Refer to RAM
disk.
RAM
Refresh - Refer to
refresh.
RAM-resident
program - Refer to
Terminate-and-stay-resident program.
Random
access - Refer to
direct access.
Random-access
file - File whose
records can be accessed in any order, instead of sequentially. You can
access files on a hard drive or diskette randomly, because the head can
glide the platter directly to the location of the file. Tape drives must
spin through the tape sequentially to reach the file you need, taking a
lot longer to access.
Random-access
memory (RAM) - Standard
type of memory that is read from and written to by the CPU and hardware.
Information in RAM can be stored and accessed randomly, and therefore,
more rapidly. RAM, which is also called main memory, is the vital
workspace of computing. The more RAM a system contains, the more
information it can handle, and the more programs it can run, at one time.
Note, however, that just because a system contains a large amount of
memory does not mean that all programs will run, program may require
certain amounts of different portions of memory such as conventional
memory which is always 640KB no matter how much memory you may have. See
our Ram Diagram for a description
of each portion of memory.
Range
- A selection of cells
in a spreadsheet that are manipulated as a group. The group can consist
of a row, a column, or a block made up of both. The selected cells must
be adjacent to one another.
RAS
- Signals that your CPU or other device (like the processor on your video
card) sends to your RAM. They tell a circuit in your RAM module that the
row address line is correct.
Raster
- Lines on the inside
of the screen traced by an electron beam to create an image called
horizontal scan lines. These lines appear on a monitor or a TV screen.
Raster
display - A monitor or
TV that presents images on-screen line by line.
Raster
graphics - A digital
method for creating a picture or image using complex series of dots.
Compare to object-oriented graphics.
Raster
image processor (RIP) - A
device that transforms a vector image into a bit-mapped or raster image,
usually in preparation for printing.
Rasterization
- Converting
object-oriented graphics to raster (bit-mapped) graphics, using a raster
image processor (RIP). Vector graphics are collections of lines, but
monitors and printers handle images as sets of dots, so images must be
rasterized before they can be displaced on a monitor or printer.
Rasterize
- Refer to
rasterization.
Raster-scan
display - Refer to
raster display.
Raw
data - Information
that has been gathered but not processed.
RDBMS
- Refer to Relational
database management system.
Read
- To input information
from an outside source.
Reader
- Refer to card
reader.
Read
error - Failure by
either a computer or its source while in the process of inputting
information into the computer.
README
file - A text file
containing information for the user. README files are included with
software to give users instructions and additional help for a particular
software program, driver, update...
Read-only
- Stored data that can
be accessed but not altered. Usually this term refers to information that
can't be physically altered.
Read-only
access - Type of
access privilege that permits the reader to view a file but not alter it.
Read-only
memory (ROM) - Type of
memory that contains data that can be read, but not changed. Unlike RAM,
which is cleared of data when the computer's electricity supply is cut
off, ROM is not dependent upon electricity and, thus is able to retain
the contents of its memory, regardless whether the computer is currently
powered up. ROM generally contains data that tells a CPU how to conduct
its business; this data is generally built into the chip during the time
it is manufactured.
Read-only
memory Basic Input / Output System (ROM-BIOS) - Refer
to Basic Input / Output System.
Read-only
terminal (RO terminal) - Device
that can accept data but cannot form it itself. Also called receive-only
terminal.
Read/Write
(R/W) - Having the
capabilities to both be read from and written to.
Read/write
channel - Refer to
input/output channel.
Read/write
head - Refer to head.
Read/write
memory - Refer to
Random-access memory.
Read/write
permission - An access
privilege that lets a user read and write to a file.
Real
address - Refer to
direct address.
Real-address
mode - Refer to real
mode.
Real
Mode - The ability of
a 286 or higher processor to take on the attributes of a lower 8086 or
8088 processor in order to run programs specific to those processors.
While this mode limits the processor to 1MB of RAM it still performs
better than a real 8086 or 8088 because of the higher clock speed.
Real
storage - Refer to
physical memory.
Real-time
- The normal passage
of time. For example, communications such as online chat sessions are
said to be real-time if they are fast enough to be perceived by the user
as a conversation instead of a series of messages with significant wait
between them.
Real-time
animation - An
animation method where updates to images happen at the same speed as in
the real world.
Real-time
clock - Refer to
clock.
Real-time
operating system - An
operating system designed to handle events as they happen (one in which
prompt feedback is important). For example, a real-time operating system
is needed for quick response in air traffic control or in ship
navigation, when a response is needed as things occur.
Real-time
system - A system that
deals with real-life actions in a timely fashion.
Reboot
- To restart the
computer and operating system. This term comes from the word bootstrap,
as in "To pull yourself up by your bootstraps."
Receive
data (RXD) - The
physical line that transmits received data from one source to another,
often from a modem to a computer.
Receive-only
terminal (RO terminal) - Refer
to read-only terminal.
Record
- A collection of
related pieces of information. For instance, a career center at a college
might keep a database of all students in internship. Each record in the
database would contain all the information about one student.
Record
format - Refer to
record structure.
Record
head - The part of a
tape backup drive that puts the magnetized data on the tape. On the other
hand, read/write heads are used on disk and diskette drives to place the
magnetized data on the platters.
Record
layout - The way data
fields in a record are arranged. For example, an office supply business
might keep a database of its regular customers and the types of brands of
supplies they routinely order. Each record in the database would be about
one customer. Within the record would be fields for such information as
name, address, billing procedure, and product preferences (perhaps broken
down by type of item). Record layout determines how these fields at the
top of the record, billing procedure code at the bottom of the record.
Record
length - How much
space a record takes up, measured in bytes. Also called record size.
Record
locking - A way to
keep more than one person from changing information in a record at one
time. The first user to access the record automatically locks others out.
Record
number - Way of
organizing records. Each record is given a number in sequence, which can
change with the addition or removal of subsequent records.
Record
size - Refer to record
length.
Recover
- To stabilize a PC
after an error. This often involves getting files back after a hard drive
crash.
Recoverable
error - An error that
doesn't cause system failure. For example, if a user enters incorrect
information, or information in an unacceptable format, this is an error,
but it wouldn't cause the system to crash. Instead, the user probably
would be prompted with a message telling how to correct the error.
Recovery
- A return to normal
operating conditions after an error has occurred. Recovery may involve
complex retrieval of information lost due to system errors.
Recovery
time - The length of
time it takes to return a system to normal operation after an error.
Recursion
- In programming when a function calls it self, starting the execution of
the function over again, usually on a new set of data. Recursion is used
by what is considered the fastest sorting algorithm
Red-green-blue
(RGB) - The creation
of color on a monitor through the precise combining of red, green, and
blue.
Red-Green-Blue
monitor (RGB monitor) - A
monitor that uses the red-green-blue method of color creation by
precisely combining these three colors.
Redirection
To send input or
output through a device other than the one usually used for that
operation. For example, output can be redirected so a saved file goes to
the A: drive instead of the C: drive.
Redlining
- A way of signifying
that certain text has been edited. Redlined text isn't necessarily marked
in red; it can appear in any color, or in bold, so long as it stands out
from the other text. This technique is used to distinguish text added or
changed by one user in a document that is being by worked on by more then
one person.
Reduced
Instruction Set Computer (RISC) - Pronounced Risk. Type of Microprocessor that recognizes a relatively
limited number of instructions. Until mid 1980's most Microprocessor
manufactures used processors with an ever-larger set of instructions as
the processors became more complex. RISC however reversed this technique
being able to use reduced instruction set, with less transistors making
them cheaper to design and produce. Many of today's RISC chips support as
many instructions as yesterday's CISC chips. And today's CISC chips use
many techniques formerly associated with RISC chips.
Redundancy
check - Refer to
cyclic redundancy check.
Redundant
Array of Inexpensive (or Independent) Disks (RAID) - Category
of disk drives that employ two or more drives in combination for fault
tolerance and performance. RAID disk drives are mainly used in servers.
See RAID page for additional
information.
Reformat
- To alter a document
or to erase all information on a diskette or hard disk. In the case of a
diskette reformatted usually is done to repair it for reuse.
Refresh
- Most commonly
associated with computer CRT monitors, refresh refers to the renewal of
screen content. The higher a monitor's refresh rate, the better the
quality of the image, the standard Refresh rate is 75MHz, Refresh rates
below 75MHz can produce often-imperceptible flicker which can cause
eyestrain.
Refresh
can also refer to the recharging of dynamic RAM chips (DRAMs) so they
maintain the data they're storing. This process is known as RAM refresh.
The common refresh rates are 2K and 4K. The 2K components are capable of
refreshing more cells at a time and they complete the process faster;
therefore, 2K components use more power than 4K components.
Refresh
cycle - Recharging RAM
locations. Computers use the binary number system, in which 0s and 1s
represent two states, such as off and on or false and true. Each pulse
from the RAM controller circuitry to the chips is one refresh cycle.
Refresh
rate - The number of
times per minute that a computer screen image is renewed. A fast refresh
rate makes a screen easier to view. Good monitors have a refresh rate of
70 to 75 hertz per second or higher.
Regeneration
buffer - Refer to
video buffer.
Region
fill - In a paint
program, the act of filling in an area with a specific color or pattern.
Register
- A high-speed data
storage area the microprocessor uses to process information. Registers
usually are 16,32, or 64 bits wide.
Register
capacity - The number
of bits or bytes a register can store.
Registered
user - The person who
purchased a software package and registered it with a company by sending
the company additional information about them.
Registration
- To register with the
manufacturer, which makes the user eligible to receive benefits such as
free technical support and product updates.
Registration
card - A card included
with commercial software so the purchaser may register the copy,
entitling the user to benefits such as free technical support.
Registration
marks - Marks on a
page that help ensure that all elements are aligned properly.
Relational
database - A database
that can share information across multiple tables or files. These tables
can be linked, or related by common information. Relationships include
one-to-one, one-to-many, and many-to-many. For example, one file may
store the names of clients while another database may share clients
products which would be a one-to-many relationship. A major strength of
relational databases is that the same information can exist in multiple
file simultaneously. When records are changed in one part of the
database, the information is updated wherever else it occurs. These
databases also use a feature known as lookups, which copy information to
only one location. This is useful in cases such as invoicing, where a
changed product price would be replicated in new invoices, while the
price in old invoices would remain unchanged.
Relational
Database Management System (RDBMS) - A program that lets a user create relational databases and work with
them.
Relational
database structure - Refer
to relational database.
Relational
model - Refer to
relational database.
Relational
structure - The
organization of a relational database.
Relative
address - Refer to
indirect address.
Relative
cell reference - A
cell identification based upon how it is located relative to a
predetermined starting point on a spreadsheet. For example, a calculation
that adds the data contain in cell (X,Y) to the data contained in the
cell (X + 2, Y + 3) users relative cell reference.
Relative
coordinates - Locations
defined by their distance from a given point.
Relay
- Device that has a
set of contacts opened or closed by mechanical force created by a current
applied to a magnetic source.
Release
- A specific version
of software. The word "release" is often used instead of the
word "version" when naming products. Release also can be
applied to a queue. When something is release from a queue, it is deleted
and not processed.
Remark
- Refer to REM
statement.
Remote
- A device that is
linked to another device via communications lines, although the two may
not be in the same room or even in the same building.
Remote
access - The hookup of
a remote computer or other remote device.
Remote
communications - When
two devices transfer data via communications lines.
Remote
control software - A
type of program that lets a user access a computer system from a remote
location using a modem or network so that he can work with the system.
For example, a worker might access an office computer from home using a
modem.
Remote
terminal - A terminal
connected to a host computer but not located in a place other than the
place where the host computer is housed. Remote terminals communicate
with their computer through various types of communication lines.
Removable
diskette - A storage
device that can easily be moved from one system to another. A 3.5-inch
diskette is the most common variety of removable diskette.
Removable
hard drive - A hard
drive in a plastic or metal cartridge that can be used and removed in a
manner similar to a diskette. A major benefit of this type of hard drive
is that it can be moved from one system to another.
Removable
hard drive - A hard
drive in a plastic or metal cartridge that can be used and removed in a
manner similar to a diskette. A major benefit of this type of hard drive
is that it can be moved from one computer to another if both machines
have a bay to accommodate the removable hard drive. This lets entire
applications and documents be taken from one location to another.
Removable
media - Refer to
removable diskette.
REM
statement - Remark
statement that can be placed in system files such as the autoexec.bat or
config.sys by placing "REM
" in front of a line this would remark the line and prevent it
from loading up the next time your computer was to boot up. To remark a
line in a INI file you must place
a semicolon ";" in
front of the line.
Render
- Refer to rendering.
Rendering
- To apply color,
shading, and shadows to a computerized image to make it more realistic in
appearance.
Repaginate
- When a document's
page breaks are set again.
Repeat
counter - A device
that keeps track of the number of times a process has been carried out or
is supposed to be carried out. Counters can be used for any repetitive
process.
Repeater
- An instrument that
increases a signal's strength so it can be transmitted and received over
a greater distance without a loss in quality.
Receptive
strain injuries (RSIs)
- Refer to cumulative trauma disorders.
Replace
- To exchange one item
with another, specifically data. Many applications can be instructed to
search for any occurrence of a certain string and replace it with another
string.
Report
- A file, often
printed, containing data from a database filtered and arranged in a way
specified by the user. For instance, someone might produce a report
listing only first names and birthdays from a contact data base
containing many more data fields about a group of people.
Report
generator - An
application that lays out and prints the contents of a database according
to a user-specified format.
Repository
- A computer system's
background information, usually stored on the system itself.
Request
to send (RTS) - Communication
between two devices in which one asks if it's all right to start
transmitting data.
Reserved
character - A
character reserved for a special purpose and can't be used in naming
files, documents, or macros.
Reserved
word - A word that is
reserved for special use in programs and can't be used for naming files,
documents, or macros.
Reset
button - Button,
usually found on the front of the computer case, that lets a user restart
the computer without shutting off power to the computer. This generally
is done when the computer has locked up, and the user can do nothing
except reboot.
Resident
font - Refer to
internal font.
Resident
program - Refer to
terminate-and-stay-resident program.
Resistors
- The most commonly
used component in an electronic circuit. They restrict the flow of
current. Resistors can be either fixed or variable. A potentiometer is an
example of a variable resistor.
Resize
- To change the size
of a graphical element. Often refers specifically to changing the size of
a window in a graphical user interface.
Resolution
- The image quality of
a printer or monitor. In monitors, the resolution is measured by the
number of pixels in a given area.
Resolution
enhancement - A way of
increasing and thus improving a printers resolution.
Resource
- An item either
hardware or software that is available for a computer to access during an
operation. A resource can be accessed by a single computer or through a
network and includes items such as a systems hard drive or a shared
printer.
Response
time - Elapsed time
between a request for information and the return of that information or
notice that it couldn't be found. This can been the time between when a
user enters a command and the computer carries it out or the time it
takes a memory circuit to storage device to return information to the
CPU.
Restart
- Refer to reboot.
Restore
- Making a window in a
graphical user interface return to its original configuration. Restore
also refers to the process of reassembling files for a back-up copy such
as a DAT to a hard drive, where they originally resided. More generally,
it may refer to the recovery information that has been lost or erased.
Restricted
function - A computer
operation that only can be performed by the CPU running in a specific
mode.
Result
set - The information
produced as the result of an operation, specifically in databases.
Retrieve
- To find a piece of
data and bring it to an active application. Information can be retrieved
from memory or a storage medium such as a diskette.
RETURN
key - Refer to enter
key.
Reverse
stroke - Refer to
backslash.
Reverse
video - A display in
which the usual color scheme of text and background has been switched to
place emphasis on certain characters or sections of text.
Revert
- Calls up the version
of a document that was previously saved.
Rewrite
- A do over; in
documents, this means to reword or edit sentences, paragraphs and pages.
In data storage, rewrite means to save over a file with the same file.
RF
- Refer to radio
frequency.
RF
shielding - Refer to
radio frequency shielding.
RGA
connector - A
Connector used to connect audio and video devices to some video adapters
and sound cards. The name comes from the common Radio Corporation of
America (RCA) speaker connector. A more generic term is phone plugs or
phone jacks.RGB - Refer to
red-green-blue.
RGB
display - Refer to
red-green-blue monitor.
RGB
monitor - Refer to
red-green-blue monitor.
Ribbon
cable - A thin cable
that looks like a seat belt, or duct tape, with wires placed side by
side. These cables are the type used inside the computer to send and
receive data for specific devices such as a hard drive or CD-ROM. These
cables are usually Grey and have a color stripe or color dotted stripe on
one of the edges to indicate pin one.
Rich-Text
Format (RTF) -A
cross-platform, cross-application text document format. Rich text format
includes some, but not all, of the formatting information (such as bold
and italics) included in many word processor-created documents.
Right
justify - Page
formatting that aligns text along the right side of the page. This layout
has a ragged left edge and a straight right edge.
Rigid
Disk - Refer to hard
disk.
Ring
network - Refer to
ring topology.
Ring
sequence - The order
in which devices are connected to a token-ring network.
Ring
status - The condition
of a computer on a token-ring network. Specifically, whether a station is
attached to a multistation access unit (MAU), which is a central
connection point for the ring.
Ring
topology - A network
topology that takes the shape of a circle. Each computer in the network,
or node, is connected to the next with small sections of cable. messages
sent from one node travel around the ring until they reach the right
node, moving in one direction only. Also called a ring network.
RIP
- Refer to raster
image processor.
RISC
- Refer to Reduced
Instruction Set Computer.
RJ-11
- Name of a standard
telephone connector.
RJ-45
- Name for one type of
Ethernet connector. Is a type of plug for network adapters that is
frequently used with Ethernet connections.
RLE
- File extension for
graphics that have been reduced using run length limited encoding. The
longer the run, the greater the compression.
RLL
encoding - Refer to
run-length limited encoding.
Robot
- Machine designed to
respond to input from its surroundings and make changes based on that
input. Often robots are made to re-create human actions, such as lifting,
welding, or other industrial jobs.
Robotics
- The field of
studying dealing with robots.
Robustness
- A quality of
hardiness; the ability to continue working properly in unusual or
difficult situations. In computing, this may refer to either the
hardware's physical capability, or software's ability to handle unusual
situations without crashing.
Rollback
- When a computer user
runs into serious problems in a program, rollback is the process of
returning the computer to its previously secure position.
Roll
in - To load memory
areas from disk to virtual memory.
Roll
out - To store areas
of virtual memory on disk.
ROM
- Refer to read-only
memory.
Roman
- Type of font. Roman
characters are straight up and down opposed to italic which is slanted.
ROM
BASIC - Before BASIC
was stored in read-only memory (ROM), users of computers with this
language had to load it from disk or tape each time the computer was
turned on.
ROM
BIOS - Refer to Basic
Input/Output system.
ROM
card - Plug-in card,
similar to a PC card, that holds programs in read-only memory.
ROM
cartridge - Plug-in
card similar to a ROM card, but larger.
Root
- The highest level in
a hierarchy; in computer systems, this usually refers to the main
directory such as C:\>.
Rotational
delay - How much time
passes between the request for information located on a disk and when the
sector rotates to the read / write head, where the information then can
be retrieved.
RO
terminal - Refer to
read-only terminal.
Round
robin - Allowing more
than one device access to resources, in turns. Each device or process
uses the resources, and then the resources are allocated to the next
device or process in the line. This is comparable to round robin letters
used in many large families and groups, in which each person reads and
adds to the letter before mailing it to the next person on the list.
Router
- The part of a
communications network that receives transmissions and forwards them to
their destinations using the shortest route available. Data may travel
through multiple routers on the way to its destination.
Routine
- Executable section
of code in a program.
Routing
- The path a message
takes from its point of origin to its destination on a network.
Row
- Data laid out in a
horizontal line.
RSI
- Refer to cumulative
trauma disorders.
RTF
- Refer to rich-text
format.
RTS
- Refer to request to
send.
Rubber
handling - In graphics
programs, when a user grabs one portion of a line or image and moves it
while other parts stay anchored, causing the line or image to stretch.
RUBOUT
key - Refer to
Backspace key.
Rule
- A solid line used in
page layout to separate columns or make the page more aesthetically
pleasing.
Rule-based
system - Refer to
expert system.
Ruler
- Similar to a
physical ruler, this ruler is placed at the top of application windows to
denote margins and other typographical guides. Most programs give the
user the option to display or hide the ruler.
Run
- To begin a program.
Run
around - Placing or
wrapping text around a graphic or image on a page.
Run-length
limited encoding (RLL encoding) - A way or storing information on a hard drive. This method of storage is
carried out by hardware in the disk controller and is less prevalent than
the modified frequency modulation (MFM) encoding scheme.
Running
foot - Test that
appears in the bottom margin of a page, such as the page number.
Running
head - Text that
appears in the top margin of the page, such as the title of the page.
Runs
on - The ability of a
program to work on a certain kind of a computer. For example, a software
package may be labeled "Runs on Pentium based computers" which
means the program runs on a Pentium system.
Runs
under - The ability of
a program to work with an operating system or environment. This may imply
that the software only works with that operating system. For example
"Developed for Windows 95."
Run
time - How long it
takes a program to run.
Runtime
error - An error that
takes place while a program is running.
RXD - Refer to receive data.
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