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