Introduction to Computers

Introduction to Computers

Topics of Discussion

1. What are Computers?
2. History of Computers
3. Components of a Computer system.
4. Operating System

1. What are Computers?

A device that receives Input (Data), performs Processing and produces the Output (information).

2. History

n      Often referred to in reference to the different generations of computing devices.

n      Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices.

First Generation - 1940-1956: Vacuum Tubes

n      The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms.

n      Very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.

n      Relied on machine language to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.

n      The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

Second Generation - 1956-1963: Transistors

n      Transistors replaced vacuum tubes in the second generation of computers.

n      The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube.

n      Second-generation computers still relied on punched cards for input and printouts for output.

n      Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words.

n      High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN.

n      These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.

Third Generation - 1964-1971: Integrated Circuits

n      The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

n      Users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.

n      Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

Fourth Generation - 1971-Present: Microprocessors

n      The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer - from the central processing unit and memory to input/output controls - on a single chip.

n      In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

n      As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.

Fifth Generation - Present and Beyond:

n      Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today.

n      The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

Computer Components

n      A computer system consists of:

n      Hardware.

n      Software.

Hardware

n      The pieces of equipment that make up a computer system.

n      Consists of

n      Motherboard

n      CPU (Processor)

n      Memory

n      Key Board

n      Monitor

n      Other Peripherals

Motherboard

n      Contains the Microprocessor and control devices.

n      Communication channel on the motherboard is called BUS

n      Bus is used for communicating with the different devices of a computer system.

n      Speed of BUS is another important factor for the measurement of computer speed.

Central Processing Unit (CPU)

n      A chip located on the motherboard that performs all the operations of the computer.

n      CPU referred as the brain of the computer because it administers the functions of other components of a computer system.

n      CPU also performs all instruction as lay down in the software program or entered by the user.

Memory

n      Also called as the RAM (Random Access Memory).

n      Another memory is ROM (Read only Memory) is also called BOIS

n      Measured is Bytes (Units of memory).

n      One byte is equal to 8 bits ( bit is smallest addressable unit in computer)

n      1024 bytes are equal to 1-Kbytes

n      1024 Kbytes equal to 1 MB

n      Use for temporary data storage.

n      The program or application to be executed by the computer is stored temporarily in the RAM.

Peripheral Device

n      A device that is connected to the computer through the bus.

n      Not part of the central computing machinery.

n      Examples are mouse, monitor, hard drives, CDs, keyboards, printers etc.

Monitor

n      An output device that displays the all the messages and result of the processing.

n      Connected to the Video card  on the motherboard through the cable

n      Monitor are of two types

n      CRT Standard flat screen monitor (generate heat and consume electricity equal to one 20” TV)

n      LCD Liquid crystal display (generate no heat and consume 12 volts only and also less space)

n      The computer sends a signal to the video card, telling it what character, image or graphic to display. The video card converts that signal to a set of instructions that tell the display device (monitor) how to draw the image on the screen.

n      The image you see on the monitor's screen is made up of thousands of tiny dots called pixels.

Mouse

n      An input device that translates movements on a horizontal surface into movements of a pointer on the computer screen.

n      The main goal of any mouse is to translate the motion of your hand into signals that the computer can use.

Keyboard

n      An input device.

n      A typical keyboard has four basic types of keys:

n      Typing keys

n      Numeric keypad

n      Function keys

n      Control keys

Hard Disk

n      The permanent storage media.

n      The hard disk drive is the "data center" of the PC.

n      Hard disk is the most important of the various types of permanent storage media.

n      The storage capacity of the modern hard disk ranges from 20 to 100 Gigabytes.

n      Works both as an input and output device.

n      In a PC it is identified normally by the drive Letter C:.

n      Made up of the magnetic material.

Floppy Disks

n      A circular piece of thin, flexible magnetic media encased in a square or rectangular wallet.

n      A portable medium used for storing computer data, readable by a computer with a floppy disk drive.

n      Capacity of disk is 1.2 MB

n      Not a reliable backup media

n      These disks are known as floppy disks (or diskettes) because the disk is flexible.

n      Mainly come in 3.5 inches and 5.25 inches diameter with the storage capacity of 1.2MB and 1.4MB respectively.

n      Also come in high capacity disk of 100 and 200 MB

Compact Disk (CD)

n      Another type of mass storage medium Comes in CD Read Only and CD Rewritable formats.

n      Uses infrared technology to read and write data.

n      Stores about 650 to 850 MB of data

n      A new technology called DVD comes with 7 GB to 17 GB of data. Stores data in multiple layers.

Software

n      The programs that makes the computer system usable.

n      Communicate with the Computer System.

n      Divided into :

n      Operating System.

n      Application Software.

Microsoft Windows

n      One of the leading operating system developed by Microsoft Corp.

n      Consists of Graphical User Interface (GUI) that displays a desktop which is a rectangular area that lets you view and use specific computer feature through the help of icons.

n      Another operating system is Linux

Starting and Logging on to Windows

n      Turn on the Monitor

n      Turn on your Computer

n      Press <Ctrl>+<Alt>+<Delete> keys on the key board to start the logon procedure

n      Enter your User Name and Password and press <Enter>

Desktop

n      Working environment of the windows Operating system.

n      The screen displayed at the start up of the windows operating system.

Desktop Components

n      The desktop contains

n      Start Button

n      Icons

n      Task bar

Start Button

n      Click the mouse on this button to view and navigate through all the programs of the windows

Icons

n      The little pictures on the desktop.

n      You can click on these icons to access programs and files etc.

n     The most common icons are of

n       My Computer.

n       Recycle Bin.    

                     

My Computer

n      My Computer stores information about your computer system.

n       It contains icons which give you access to your disk drives.

n      It also provides access to the Control Panel (also accessible via the Start Menu), where you can adjust settings for your system.

Recycle Bin

n      This is the equivalent of the wastepaper bin in your office.

n      Contains the deleted files.

Task bar

n      This is the long strip at the bottom of the screen.

n      Used to switch back and forth between opened files.

Control Panel

n      Contains specialized tools that are used to change the way Windows looks and behaves.

n      Some of these tools help you adjust settings like Date and Time, Network Connections etc.

n      Other tools help you set up Windows so that your computer is easier to use.

n      To open Control Panel, click Start, point to Settings, and then click Control Panel using the mouse.

Basic Mouse Operations

n      You communicate with your computer with a mouse.

n      When you move your mouse, your mouse pointer moves along with it.

n      You access icons and perform tasks on your computer by moving your mouse, and clicking the mouse buttons.

n      The primary mouse button is the left button, and the secondary button is the right button.

n      The left mouse button is for double clicking, accessing, dragging, highlighting, etc.

n      The right mouse button is for locating properties and other submenus on your computer.

Folders

n      An object that can hold multiple files or documents.

n      They are also known as the directories.

Files

n      A collection of information that a computer uses. It is always in a particular format. For example, if you created a Microsoft Word document, the file is saved so that Microsoft Word can open and read it.

n      Files are made up of the File name, and the Extension.

n      The file name is the first part of the File. This name can be up to 255 characters long in Windows and is set by the user.

n      It should be descriptive of what the particular file or document consists.

n      The extension is the second part of the name of the File. It is three characters long and tells the computer to associate the file with a particular program.

Creating Folder

n      Double click the My Computer Icon on the desktop to open the My Computer Window.

n      Double click any drives from the Hard Disk Drives section.

n      Select File>New>Folder from the main menu to make the new folder in the selected hard drive.

n      A new folder is displayed with the default name, New Folder, selected.

n      Type a name for the new folder, and then press ENTER.

Copying Files and Folders

n      Click My Computer Icon

n      Select the drive or folder you want to work with.

n      Click the file or folder you want to copy.

n      On the Edit menu, click Copy.

n      Open the folder or where you want to copy.

n      On the Edit menu, click Paste.

Deleting Files and Folders

n      Click My Computer Icon

n      Select the drive or folder you want to work with

n      Click the file or folder you want to delete by pressing the Delete key.