Operating Systems

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Operating Systems
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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.

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Some widely used operating systems

• DOS
• UNIX
• MacOS
• Windows

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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

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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)

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Command Line Interface Examples

• To tell the computer to copy file1into a (new)
  file named file2
• DOS
• A\gt copy file1 file2
• A\gt
• Unix
• 1gt cp file1 file2
• 2gt

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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.

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• GUI (or point-and-click) designs were developed
  at Xerox Palo Alto Research Center in the late
  1970s 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.

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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