Operating Systems What is an operating system

Operating Systems

What is an operating system? n The software that manages your computer: n n n Maintains your files finds files copies files deletes files links your printer to your application formats disks, etc.

Some widely used operating systems n n DOS UNIX Mac. OS Windows

DOS n n 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 n n n 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 file 1 into a (new) file named file 2: n DOS A: > copy file 1 file 2 A: > n Unix 1> cp file 1 file 2 2>

Windows n n n 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) n 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.

n n 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 Mac. Intosh computers, introduced in 1984.

Why a GUI rather than commands? n Graphical user interfaces are n n n easy to learn but perhaps slower to use because of pointing device Command line interfaces are n n hard to learn and easy to forget but perhaps faster to use for experienced user