Glossary » I/O Devices

access key

A key on the keyboard used as a shortcut to issue menu commands (underlined items in Windows menus).

ambient media

devices that monitor information states and display the information continuously in the periphery (that is, without the user needing to consciously attend to the display). This allows the user to be aware of the peripheral information without making an explicit…

articulatory directness

how well the form and behavior of an input device (degrees of freedom, range of motion, discreteness of states) corresponds to the type of input values a user needs to express.

auditory I/O

sounds used for input and output, which may include speech, musical sounds, naturalistic sounds, and artificial waveforms. Sound as output has the advantage of being accessible to the visually impaired, of being heard even the user needs to be looking…

barrel-tap

holding down the button on a pen (barrel button) while tapping — used as an input technique in pen-based systems.

bat

a flying mouse; an input device that permits pointing to objects in 3-dimensional space by moving the bat around in the air, similar in spirit to the use of a mouse to point to objects in 2-dimensional space.

beaming

sending information by infrared from one device to another, as with remote control devices or when transferring electronic business cards between handheld computers.

binocular display

also stereoscopic display; a display that is composed of 2 separate displays which are directed separately to the left and right eyes. The viewpoint is slightly different for each, reflecting the slightly different view each eye would have when embedded…

biometrics

the detection and use of unique identifying physical characteristics in identifying users of a system, typically for security reasons to restrict access without the use of passwords. Examples of biometric devices include: thumbprint readers, retina scanners, body heat scanners, and…

bit depth

the number of bits used to represent the color of an individual pixel on a computer screen. A bit depth of 1 would represent that the pixel could only be on-off — a black-and-white display. 8-bit displays can display 256…

blow-suck tube

an input device for users with limited mobility; a blow-suck tube is placed in the mouth and blown through. It can be used in conjunction with a tongue-activated joystick to move a pointer around and make selections.

brain-computer interface

or brain-body interface; an interface directly controlled by brain waves as opposed to physical movement. Current state-of-the-art can only distinguish a few brain states, so such interfaces usually are led by yes-no decisions. These interfaces require training and are currently…

button

an input device both on the screen and in the physical world, typically used to select among on/off states or to activate a command.

carpal tunnel syndrome

(CTS) a problem with swelling or inflammation around the median nerve in the wrist, causing pain or numbness. Poor wrist support and posture during extensive typing is considered a contributing factor. Some ways to prevent it include improved posture, wrist…

chording

an input mechanism which requires pushing more than one button simultaneously in different patterns to represent different letters or commands.

“Chording keyboards” allow rapid entry of letters and words which can allow faster typing than conventional keyboards and permits one-handed…

click wheel

the thumbwheel on an iPod music player that allows scrolling through options with a circular motion of the thumb and can also be pressed in one of 4 directions to activate other commands (on the iPod: menu, back, forward, and…

CMYK

cyan-magenta-yellow-black; a color model that specifies any given color as the combination of 4 base colors, commonly used in printers. While the RGB model is based on combining projected colors (an additive system), the CMYK model is based on using…

command key

or Apple key; a key on the Macintosh used as a shortcut to issue commands, by holding down the command key and pressing another letter. The command key is usually labeled with a small cloverleaf symbol on the Macintosh. The…

control key

CTRL; a key on used as a shortcut to issue commands (such as menu commands) and to type in certain non-alphanumeric values by holding down the control key and pressing another letter. The control key has been around a long…

control selectivity

the degree to which a control can be manipulated without accidentally activating other controls. A common problem is to position buttons or keys too closely, leading to the wrong button being pressed.

control sensitivity

the ease with which a control can be activated or set to a certain level. Less sensitive devices require greater effort.

CRT

cathode ray tube; the traditional technology used for televisions and computer monitors which technically involves shooting an electron beam into phosphors embedded in the screen to temporarily light them up.

cursor key

a key on the keyboard that moves the cursor position up, down, left, or right. On keyboards without them, this is often simulated with the numeric keypad used to move the cursor, or some key combination used to indicate cursor…

dataglove

a glove with sensors to detect hand position and orientation, and finger position, used to provide 3-dimensional input, especially in virtual reality (VR) systems.

device independence

the ability for software to work with a variety of different input or output devices without having to worry about which ones exactly the user is using. This enables users, such as the disabled, to use whatever devices are most…