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Operating SystemsComputer Technology Notes #3
Development of Computers
1st Generation computers (1940-1956)
• Used vacuum tubes.• Vacuum tubes are electronic
devices that control the flow of electrons.
• Had no operating systems – the user programmed the computer by physically entering the computer and programming by hand
1st Generation Computers• Could only do one thing at a time
• Used custom application programs, which were made for the specific task that the computer was to perform.• Still no operating systems• Instructions were necessary for every aspect of
the computing job.• UNIVAC was the first commercial computer,
used by the U.S. Census Bureau starting in 1951.• ENIAC was another early computer
2nd Generation computers (1956-1963)• Used transistors
• Transistors performed functions similar to vacuum tubes, but they were smaller, cheaper, less power-hungry, and more reliable.
• Ran programming language compilers:• Used English like commands rather
than binary numbers. • COBOL and FORTRAN were
programming languages• Made it possible to develop
software
3rd Generation computers (1964-1971)• Used integrated circuits
• Placed on silicon chips (semiconductors)• Operating systems in development
• Users could start to communicate through keyboards, monitors, and operating systems
• Computers started to become accessible to more people
4th Generation computers (1971-Present)• Used general-purpose
microprocessors.• Thousands of integrated circuits
were built onto a single chip• Operating systems were
developed:• 1981-IBM introduced first
personal computer• 1984-Apple introduced
Macintosh
5th Generation computers (Present and Beyond)• Artificial Intelligence, still
in development• Nanotechnology
• Extremely small computers• Computers will be able to
respond to natural language and will be capable of learning
Operating System Software• The operating system is a set of programs that
perform certain basic functions with a specific type of hardware.
• The functions of the operating system are:• Starting the computer• Managing programs• Managing memory• Handling messages from input and output
devices• Enabling user interaction with the computer
Platform• Underlying hardware and software that are built
to work together• Two popular platforms:
• PC (Windows)• Mac (Apple)
Multitasking-One of the Functions of an Operating System• Running more than one program at a time.• Making sure that the instructions and data from one area
of memory don’t interfere with memory allocated for other programs.
• You can still only work on one program at a time, but multitasking allows you to easily switch between programs
Example of MultitaskingBackground
application –it is open and available, but you aren’t working on it right now
Foreground application –this is the application you are working on right now
Types of User Interfaces
• The user interface allows us to communicate with the computer. There are three types:• Graphical user interface (GUI)• Menu-driven• Command-line
GUI (Graphical User Interface)• Uses graphics to create a desktop environment• Icons (small pictures) represent computer
resources• Programs run within on-screen windows• Pronounced “gooey”
Menu-driven User Interface
Text-based menus are used to show all of the options available to the user. No mouse is used
Command-Line InterfaceThe user is required to type keywords or commands in order to enter data or give instructions.
MS-DOS
WINDOWS XP MAC OS
WINDOWS 8UNIX
Popular Operating Systems
Microsoft WindowsWindows 1.0 (1985)Windows 2.0 (1987)Windows 3.x (1990-1992)Windows NT (1993)Windows 95 (1995)Windows 98 (1998)Windows 2000 (2000)Windows ME (2000)Windows XP (2001)
Definitions
• Program• Set of detailed, step-by-step instructions that tell a
computer how to solve a problem or carry out a task.
• Application Software (an “app”)• A computer program that is written to accomplish a specific
task. Examples: Word, Excel, and PowerPoint
Basic definitions
• Drive• A location on a network that is set aside for
the collection of data. • Folder
• The subdirectory or subdivision, of a drive that can contain files or other folders.
• File• A named collection of data that exists on a
storage medium, sometimes called a document
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