A desktop system unit that houses the computer’s processor, memory, and monitor in a single unit.
The set of programs on a computer that helps a user carry out tasks such as word processing, sending e-mail, balancing a budget, creating presentations, editing photos, taking an online course, and playing games.
The width-to-height proportion of a monitor.
binary digit (bit)
A digit that corresponds to the on and off states of a computer’s switches. A bit contains a value of either 0 or 1.
The language computers use to process data into information, consisting of only the values 0 and 1.
A method of optical storage for digital data, developed for storing high-definition media. It has the largest storage capacity of all optical storage options.
A type of wireless technology that uses radio waves to transmit data over short distances (approximately 30 feet for Bluetooth 1 and 60 feet for Bluetooth 2). Often used to connect peripherals such as printers and keyboards to computers or headsets to cell phones.
A measure of the greatest amount of light showing when a monitor is displaying pure white; measured as candelas per square meter (cd/m2) or nits.
Eight binary digits (bits).
compact disc (CD)
A method of optical storage for digital data; originally developed for storing digital audio.
central processing unit (CPU or processor)
The part of the system unit of a computer that is responsible for data processing (the “brains” of the computer); it is the largest and most important chip in the computer. The CPU controls all the functions performed by the computer’s other components and processes all the commands issued to it by software instructions.
The process of starting a computer from a powered-down or off state.
A data-processing device that gathers, processes, outputs, and stores data and information.
A port that enables the computer (or other device) to be connected to other devices or systems such as networks, modems, and the Internet.
A measure of the difference in light intensity between the brightest white and the darkest black colors that a monitor can produce. If the contrast ratio is too low, colors tend to fade when the brightness is adjusted to a high or low setting.
cursor control key
A set of controls on standard keyboards that moves the cursor (the flashing symbol on the monitor that indicates where the next character will be inserted); also known as an arrow key.
Numbers, words, pictures, or sounds that represent facts, figures, or ideas.
A computer that is intended for use at a single location. A desktop computer consists of a case that houses the main components of the computer, plus peripheral devices.
digital video disc (DVD)
A method of optical storage for digital data that has greater storage capacity than compact discs.
digital video interface (DVI)
Video interface technology that newer LCD monitors, as well as other multimedia devices such as televisions, DVD players, and projectors, use to connect to a PC.
A special shelf inside a computer that is designed to hold storage devices.
A specially designed computer chip that resides inside another device, such as a car. These self-contained computer devices have their own programming and typically neither receive input from users nor interact with other systems.
How a user sets up his or her computer and other equipment to minimize risk of injury or discomfort.
A port that is slightly larger than a standard phone jack and transfers data at speeds of up to 10,000 Mbps; used to connect a computer to a DSL or cable modem or a network.
expansion card (adapter card)
A circuit board with specific functions that augment the computer’s basic functions and provide connections to other devices; examples include the sound card and the video card.
external hard drive
An internal hard drive that is enclosed in a protective case to make it portable; the drive is connected to the computer with a data transfer cable and is often used to back up data.
FireWire 400 (IEEE 1394)
An interface port that transfers data at 400 Mbps.
One of the fastest ports available, moving data at 800 Mbps.
A drive that plugs into a universal serial bus (USB) port on a computer and stores data digitally. Also called USB drive, jump drive, or thumb drive.
flash memory card
A form of portable storage; this removable memory card is often used in digital cameras, portable media players, and personal digital assistants (PDAs).
A type of monitor that is lighter and more energy-efficient than a CRT monitor; often used with portable computers such as notebooks.
About a billion bytes.
One billion hertz.
A device that holds all permanently stored programs and data; can be located inside the system unit or attached to the system unit via a USB port.
Any part of the computer that you can physically touch.
A power-management mode that saves the current state of the current system to the computer’s hard drive.
high-definition multimedia interface (HDMI)
A compact audio–video interface standard that carries both high-definition video and uncompressed digital audio.
A printer that has tiny hammer-like keys that strike the paper through an inked ribbon, thus making a mark on the paper. The most common impact printer is the dot-matrix printer.
Data that has been presented or organized in a meaningful fashion.
A nonimpact printer that sprays tiny drops of ink onto paper.
A hardware device used to enter, or input, data (text, images, and sounds) and instructions (user responses and commands) into a computer. Some input devices are keyboards and mice.
internal hard drive
A hard drive that is installed inside the system unit.
A hardware device used to enter typed data and commands into a computer.
A unit of computer storage equal to approximately one thousand bytes.
A nonimpact printer known for quick and quiet production and high-quality printouts.
Comprises computing devices, software, or peripherals that use techniques, parts, and methods from an earlier time that are no longer popular.
liquid crystal display (LCD)
The technology used in flat-panel computer monitors.
A large, expensive computer that supports hundreds or thousands of users simultaneously and executes many different programs at the same time.
A unit of computer storage equal to approximately 1 million bytes.
A measure of processing speed equal to 1 million hertz.
A device that allows you to capture sound waves, such as those created by your voice, and transfer them to digital format on your computer.
An expansion card that provides the computer with a connection to the Internet via conventional phone lines.
A port that uses a traditional telephone signal to connect a computer to the Internet.
monitor (display screen)
A common output device that displays text, graphics, and video as soft copies (copies that can be seen only on screen).
A special circuit board in the system unit that contains the central processing unit (CPU), the memory (RAM) chips, and the slots available for expansion cards; all of the other boards (video cards, sound cards, and so on) connect to it to receive power and to communicate.
A hardware device used to enter user responses and commands into a computer.
A device that combines the functions of a printer, scanner, copier, and fax into one machine.
A computing device that runs a full-featured operating system but weighs two pounds or less.
network interface card (NIC)
An expansion card that enables a computer to connect other computers or to a cable modem to facilitate a high-speed Internet connection.
A printer that sprays ink or uses laser beams to make marks on the paper. The most common nonimpact printers are inkjet and laser printers.
Permanent storage, as in read-only memory (ROM).
A small, compact portable computer.
operating system (OS)
The system software that controls the way in which a computer system functions, including the management of hardware, peripherals, and software.
A hardware device that uses lasers or light to read from, and maybe even write to, CDs, DVDs, or Blu-ray discs.
A mouse that uses an internal sensor or laser to control the mouse’s movement. The sensor sends signals to the computer, telling it where to move the pointer on the screen.
organic light-emitting diode (OLED) display
A display that uses organic compounds to produce light when exposed to an electric current. Unlike LCDs, OLEDs do not require a backlight to function and therefore draw less power and have a much thinner display, sometimes as thin as 3 mm.
A device that sends processed data and information out of a computer in the form of text, pictures (graphics), sounds (audio), or video.
A device such as a monitor, printer, or keyboard that connects to the system unit through ports.
A single point that creates the images on a computer monitor. Pixels are illuminated by an electron beam that passes rapidly back and forth across the back of the screen so that the pixels appear to glow continuously.
A large printer that uses a computer-controlled pen to produce oversize pictures that require precise continuous lines to be drawn, such as maps and architectural plans.
An interface through which external devices are connected to the computer.
A power supply regulates the wall voltage to the voltages required by computer chips; it is housed inside the system unit.
A common output device that creates tangible or hard copies of text and graphics.
Manipulating or organizing data into information.
A device that can project images from your computer onto a wall or viewing screen.
A keyboard that gets its name from the first six letters on the top left row of alphabetic keys on the keyboard.
random access memory (RAM)
The computer’s temporary storage space or short-term memory. It is located in a set of chips on the system unit’s motherboard, and its capacity is measured in megabytes or gigabytes.
read-only memory (ROM)
A set of memory chips, located on the motherboard, which stores data and instructions that cannot be changed or erased; it holds all the instructions the computer needs to start up.
The clearness or sharpness of an image, which is controlled by the number of pixels displayed on the screen.
The measurement (in milliseconds) of the time it takes for a pixel to change color; the lower the response time, the smoother moving images will appear on the monitor.
S-video (super video)
A type of technology used to transmit video signals; used on newer LCD monitors, as well as other multimedia devices such as televisions, DVD players, and projectors.
A low-power mode for electronic devices such as computers that saves electric power consumption and saves your computer settings where you left off. When the computer is “woken up,” you can resume working more quickly than when cold booting the computer.
solid state drive (SSD)
A drive that uses the same kind of memory that flash drives use, but can reach data in only a tenth of the time a flash drive requires.
An expansion card that attaches to the motherboard inside the system unit and that enables the computer to produce sounds by providing a connection for the speakers and microphone.
An output device for sound.
A pen-shaped device used to tap or write on touch-sensitive screens.
A specially designed computer that can perform complex calculations extremely rapidly; used in situations in which complex models requiring intensive mathematical calculations are needed (such as weather forecasting or atomic energy research).
Speaker systems set up in such a way that they surround an entire area (and the people in it) with sound.
The set of programs that enables a computer’s hardware devices and application software to work together; it includes the operating system and utility programs.
The metal or plastic case that holds all the physical parts of the computer together, including the computer’s processor (its brains), its memory, and the many circuit boards that help the computer function.
A notebook computer designed specifically to work with handwriting recognition technology.
1,099,511,627,776 bytes or 240 bytes.
A printer that works either by melting wax-based ink onto ordinary paper (in a process called thermal wax transfer printing) or by burning dots onto specially coated paper (in a process called direct thermal printing).
A type of monitor (or display in a notebook or PDA) that accepts input from a user touching the screen.
A small, touch-sensitive screen at the base of a notebook keyboard. To use the touchpad, you simply move your finger across the pad to direct the cursor.
A mouse with a rollerball on top instead of on the bottom. Because you move the trackball with your fingers, it doesn’t require much wrist motion, so it’s considered healthier for your wrists than a traditional mouse.
A small, joystick-like nub that enables you to move the cursor with the tip of your finger.
universal serial bus (USB) port
A port that can connect a wide variety of peripheral devices to the computer, including keyboards, printers, mice, smartphones, PDAs, flash drives, and digital cameras.
video card (video adapter)
An expansion card that is installed inside a system unit to translate binary data (the 1s and 0s the computer uses) into the images viewed on the monitor.
video graphics array (VGA) port
A port to which a CRT monitor connects.
Measured in degrees, this tells how far you can move to the side of (or above or below) the monitor before the image quality degrades to unacceptable levels.
Temporary storage, such as in random access memory (RAM). When the power is off, the data in volatile storage is cleared out.
The process of restarting the system while it’s powered on.
A small camera that sits on top of a computer monitor (connected to the computer by a cable) or is built into a notebook computer and is usually used to transfer live video.