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The Evolution of User Interfaces
Graphical user interface
The next great leap forward in user interface design occurred with operating
systems. In the early days of computers, most operating systems offered
only command-line user interfaces, so programs had to create their own
pull-down menu user interfaces themselves. Therefore, every program tends
to look slightly different even if it used nearly identical pull-down menus.
To create a consistent appearance for all programs and give users the ability
to run two or more programs at the same time, operating systems soon
abandoned their clunky command-line user interfaces and adapted a graphical
user interface (abbreviated as GUI).
The main purpose of a GUI is to give users the chance to point and click the
commands they want rather than force them to type in the actual command
name.
An operating system’s GUI offered three advantages:
✦ All programs appeared with a consistent look.
✦ Each program appeared in its own window.
✦ Users could cut, copy, and paste data from one window (program) to
another.
Before GUI operating systems, such as Mac OS X or Microsoft Windows, two
programs might both display similar pull-down menus, but one program
might display it in black against a white background whereas the other program
might display it in red against a blue background. Such visual differences
might be functionally trivial, but the jarring visual differences could
make figuring out different programs harder for many people.
By forcing all programs to look similar, GUI operating systems made figuring
out programs much easier. After you knew how one program worked, you
could easily switch to another one.
✦ GUI operating systems can display individual programs in separate windows.
Previously, computers could only run a single program at a time,
and that program would gobble up the entire screen.
With GUI operating systems, each program could only appear in a separate
window. That way you could run multiple programs at a time,
arrange them in separate windows, and see and switch between each
program just by clicking a different window.
✦ GUI operating systems let you share data between separate windows. So if
one window runs a word processor and a second window runs a database,
you could copy and paste data from one program into the other. Without a