CONCURRENT PERFORMANCE OF FUNCTIONS

Graphic systems may do two or more things at one time. Multiple programs may run 

simultaneously. When a system is not busy on a primary task, it may process background

tasks (cooperative multitasking).When applications are running as truly separate tasks, the

system may divide the processing power into time slices and allocate portions to each 

application.

Data may also be transferred between programs. It may be temporarily stored on a 

"clipboard" for later transfer or be automatically swapped between programs.

THE GRAPHICAL USER INTERFACE

 A user interface is a collection of techniques and mechanisms to interact with 

something.

 In a graphical interface the primary interaction mechanism is a pointing device of 

some kind.

 This device is the electronic equivalent to the human hand. What the user interacts 

with is a collection of elements referred to as objects.

 They can be seen, heard, touched, or otherwise perceived.

 Objects are always visible to the user and are used to perform tasks.

 They are interacted with as entities independent of all other objects.

 People perform operations, called actions, on objects. The operations include 

accessing and modifying objects by pointing, selecting, and manipulating. All 

objects have standard resulting behaviors.

THE WEB USER INTERFACE

The expansion of the World Wide Web since the early 1990s has been truly amazing. Once 

simply a communication medium for scientists and researchers, its many and pervasive 

tentacles have spread deeply into businesses, organizations, and homes around the world.

Unlike earlier text-based and GUI systems that were developed and nurtured in an 

organization's Data Processing and Information Systems groups, the Web's roots were 

sown in a market-driven society thirsting for convenience and information.

Web interface design is essentially the design of navigation and the presentation of 

information. It is about content, not data.

Proper interface design is largely a matter of properly balancing the structure and 

relationships of menus, content, and other linked documents or graphics. The design goal is