Operating Systems

What is an operating system? The software that manages your

computer: Maintains your files finds files copies files deletes files links your printer to your application formats disks, etc.

Some widely used operating systems DOS UNIX MacOS Windows

DOS DOS--Disk Operating System One of the oldest PC operating

systems (Microsoft shipped first version in 1981)

Made Bill Gates a billionaire Command line interface

UNIX Very large Has many built-in programs Used on high-end systems Available in a smaller version called

Linux (created in 1991), available for free

Command line interface (first version developed at Bell Labs in 1969)

Command Line Interface Examples

To tell the computer to copy file1into a (new) file named file2:

DOSA:\> copy file1 file2A:\>

Unix1> cp file1 file22>

Windows Used by most computers in the world Graphical user interface (GUI--pronounced

‘gooey’) This interface has been standardized

across applications by Microsoft, Inc. (version 3.0 released in 1990 as a GUI to DOS) This makes it easy to learn new applications

since the icons, clicking, position and types of menus are common across applications except for commands peculiar to an application.

GUI (or point-and-click) designs were developed at Xerox Palo Alto Research Center in the late 1970’s but were never used in commercial computer systems at that time.

The first commercial use was in the original Apple MacIntosh computers, introduced in 1984.

Why a GUI rather than commands? Graphical user interfaces are

easy to learn but perhaps slower to use because of

pointing device Command line interfaces are

hard to learn and easy to forget but perhaps faster to use for

experienced user