Glossary of Computer Terms—R
R
RAID: Redundant Array
of Inexpensive Disks. A method of spreading information across several disks
set up to act as a unit, using two different techniques.
RAM: Random Access
Memory. One of two basic types of memory. Portions of programs are stored in
RAM when the program is launched so that the program will run faster. Though a
PC has a fixed amount of RAM, only portions of it will be accessed by the
computer at any given time. Also called memory.
RAM DISK (DISK
EMULATOR): A portion of a hard drive configured to emulate a
RAM. It accesses information quickly, but its data must be saved in a
non-volatile memory for future use. Otherwise, the information is lost when
power is removed.
RANDOM ACCESS: A technique of
accessing (reading) a word of data from a memory structure by the CPU. Since a
word in the memory can be accessed directly, the time required is independent
of its location (address) in the memory structure. It is sometimes called a
“direct access” method.
RANDOM ACCESS
MEMORY (RAM): A volatile, semiconductor storage structure that
accesses temporary data with a random or direct accessing method. It is more
accurately referred to as “erasable read/write” memory. Data in this memory can
be read by the CPU, edited, altered, erased, or new information written over
existing data by computer commands. Its data must be saved for future access by
writing it into a non-volatile memory. See NON-VOLATILE MEMORY and VOLATILE
MEMORY.
READ-ONLY MEMORY
(ROM): A semiconductor memory whose data cannot be erased, or overwritten; it
can only be accessed (read) for use by the CPU. The data in a ROM is of a
permanent nature and is programmed by the ROM manufacturer. In many cases, its
programmed information identifies the dedicated function of a computer. A ROM
can also be in the physical form of a module (tape or disk) that is plugged
into a computer to change its operation from one program to another.
REALAUDIO: This is a
method of playing sounds invented by Rob Glasser that creates a buffer between
the supplying server and your computer. The file is played without downloading
it completely.
REAL TIME: This is method
of processing data the moment it is received. Batch mode is a term used for a
mainframe computer dealing with data when it has the time.
REAL-TIME DATA: Time-dependent
data processed by a computer whose output data is capable of controlling other
time-related events, such as traffic control. Real time is the actual time it
takes for an event to occur.
REBOOT: To restart a
computer. In DOS, you can reboot by pressing the Alt, Control and Delete keys
simultaneously. This is called a warm boot. You can also perform a cold boot by
turning the computer off and then on again.
On Macs, you reboot by selecting the “Restart” option from the
Special menu.
REFRESH: Generally, to
update something with new data. For example, some Web browsers include a
refresh button that updates the currently display Web pages. This feature is
also called reload. To recharge a device with power or information. For
example, dynamic RAM needs to be refreshed thousands of times per second or it
will lose the data stored in it.
Similarly, display monitors must be refreshed many times per
second. The refresh rate for a monitor is measured in hertz (Hz) and is also
called the vertical frequency, vertical scan rate, frame rate or vertical
refresh rate. The old standard for monitor refresh rates was 60Hz, but a new
standard developed by VESA sets the refresh rate at 75Hz for monitors
displaying resolutions of 640x480 or greater. This means that the monitor
redraws the display 75 times per second. The faster the refresh rate, the less the
monitor flickers.
REGISTER: A temporary
storage unit for quick, direct accessibility of a small amount of data for
processing. Most computers include a set of internal registers that can be
accessed more quickly than the system’s main memory.
RESIDENT SOFTWARE:
The program(s) residing in the main memory of a computer system. For
convenience of operation, several software programs can reside in RAM after the
computer is turned on and booted, and they can be accessed quickly from within
another program.
RESOLUTION: Refers to the
sharpness and clarity of an image. The term is most often used to describe
monitors, printers, and bit-mapped graphic images. In the case of dot-matrix
and laser printers, the resolution indicates the number of dots per inch. For example,
a 300-dpi (dots per inch) printer is one that is capable of printing 300
distinct dots in a line 1 inch long. This means it can print 90,000 dots per
square inch.
RS-232-C: Identifies an
interconnection standard for serial operation. It specifies the configuration
and type of connectors in the computer’s serial I/O port(s) and peripheral
serial port(s).
ROUTER: A network
device that enables the network to reroute messages it receives that are
intended for other networks. The network with the router receives the message
and sends it on its way exactly as received. In normal operations, they do not
store any of the messages that they pass through.
RIGHT-CLICK: Using the right mouse button to open context-sensitive dropdown menus.
RIGHT-CLICK: Using the right mouse button to open context-sensitive dropdown menus.
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