Chapter One: Introduction To Computer

Chapter One: Introduction To Computer

• General IT Concepts• Computer Hardware • Types of Software

• Information Networks • The Use of Computer in our life

General IT Concepts

• What is Computer?– A computer is a programmable machine designed

to sequentially and automatically carry out a sequence of arithmetic and logical operations.

General IT Concepts

• Hardware

• Software

• Network

• Information Technology

Types of Computers

• Mainframe Computers – Mainframe Computers are used for highly critical

applications such as bulk data processing. Most of the mainframe computers have the capacities to host multiple operating systems and operate as a number of virtual machines and can thus substitute for several small servers.

Types of Computers

• Desktops – A desktop is intended to be used on a single

location

Types of Computers

• Laptops – laptop computers are optimized for mobile use.

Laptops run on a single battery or an external adapter that charges the computer batteries. They are enabled with an inbuilt keyboard, touch pad acting as a mouse and a liquid crystal display.

Types of Computers

• Personal Digital Assistants (PDAs)– It is a handheld computer and popularly known as

a palmtop. It has a touch screen and a memory card for storage of data. PDAs can also be effectively used as portable audio players, web browsers and smart phones

Hardware• Central Processing Unit and its Functions

– Performing calculation:- when there are numbers to add or other calculations to perform, it happens in the CPU.

– Controlling logic: - often your computer makes choices: which color to display, what calculation to perform, and so on. The logic of these choices is embodied in the CPU.

– Immediate access memory: - The CPU contains a small amount of fast memory to store immediate results that it will need immediately. This memory is called Cache.

– Coordinating other function: - The CPU sends instructions to other components, such as sound card, video card and hard drive telling them what to do.

Memory • RAM– When you run an application, the computer code that makes up that

application and the results of your work are temporarily stored in RAM .

– RAM is comparatively inexpensive and can be reused many times by your computer; each part of the memory can be written to or read from repeatedly.

– RAM is also volatile. That is, anything stored only in RAM is lost when turned off the computer.

Memory

• ROM– ROM is smaller area of memory that holds critical

applications that run the computer itself. Information stored in ROM is there permanently, even when the computer is turned off. Most computers use ROM to hold the basic programs that make the computer and its display come alive and become ready to hold other information.

Memory

• What is a bit?– A single bit is equal to either a numerical 1 or 0 at

any given time. Each bit of memory is like tiny switch that the computer can turn on or off. On equals 1 and off equals 0. This system is called

binary system

Memory

• A byte is 8 bits. • A kilobyte (KB) is 1024 bytes. • A megabyte (MB) is 1024 KB or roughly one

million byte. • A gigabyte (GB) is 1024 MB or roughly one

billion byte.• A terabyte (TB) is 1024 GB or roughly one

trillion byte.

Input Devices

1. A mouse is an input devices designed to be held with one hand and slide around on disk. The computer translates this movement into the movement of the cursor on your screen. The mouse has also one or more buttons that you can press to send instructions to the computer.

Input Devices

2. A keyboard is an input device that includes the standard typewriter keys and other keys such as function keys, arrow keys, and numeric keypad. The keyboard is the device most often used to input text to a computer program.

Input Devices

3. A trackball resembles an upside-down mouse. The trackball stays in one spot on your desk, with a ball facing upward. Moving the ball moves the cursor onscreen. Like a mouse, a trackball has one or more buttons that you can press.

Input Devices

4. A scanner is an input device that can convert a printed sheet of paper (or other flat object) into a file that the computer can store. Some scanners are standalone device, whereas others are built into

printer or other multipurpose devices

Input Devices

5. A touchpad is a small rectangular area, usually built into a laptop computer, where you can drag your finger to move the cursor on the screen

Input Devices

6. A light pen looks a bit like a penlight with cord coming out of the end. You can indicate a spot on your computer monitor by pointing at it with the light pen and clicking a button.

Input Devices

• A digital camera– allows you to take pictures without film by storing them in memory

inside the camera. Then by using special cable, you can load them into

the computer

Output Devices

• A Monitor– is a video display device sometimes informally called computer’s

screen. It is the main place where you will receive information from

the computer.

Output Devices

• A printer

– is an output device suited to produce printed output on paper. There are a wide variety of printers; they differ in their speed, size of the paper printed, cost and the process that they use for printing.

Output Devices

• A plotter

– is device that moves one or more pens over a piece of paper to create a drawing. Plotters are typically used for output such as architectural

drawing and mechanical design.

Storage Devices

• A diskette

– is small removable storage device, sometimes called a “ Floppy disk”

Storage Devices

• A Zip disk

– is a proprietary device about the size of a diskette but with hard plastic shell and much higher storage capacity.

Storage Devices

• A CD-ROM is a plastic disk, similar to music CD.• Internal and external hard drives are permanently

sealed magnetic storage devices that are capable of storing large amount of data. Internal hard drives are inside the housing of the computers. External hard drives are the ones that can connect to the computer outside the computer housing.

Software

• What is a Software? • Types of Software:

• Operating System Software– Operating system software is the software that provides the

basic functions of the computer.

• Application Software – all software other than the operating system, that are written

for specific reason are called application software such as accounting software, game software,

Examples of Operating System• Microsoft Windows is the most common graphical operating system used

today. Microsoft has released a number of versions of windows over the years. Windows versions commonly used in current business environment include windows XP, Vista, and window 7.

• Linux is a popular open source operating system; open source means that you can download it from the internet for free.

• DOS is text only operating system. It is created by Microsoft and it commonly refers to Microsoft MS-DOS.

• MAC OS is the most recent operating system developed by Apple

company for its Macintosh computers.

Examples of Application Software

• Accounting Software is used to track credits, debits, and other accounting data. Microsoft ERP Great Plains is example of such software.

• Web Browsing Software is used to view contents of web sites. Microsoft Internet Explorer is an example of such software.

• Desktop Publishing Software is used to create newsletters, magazines, and other documents suitable for printing. Microsoft publisher is an example of such software.

• Presentation Software is used to create slide show and other speaker aids. Microsoft Power Point Presentation is an example of such software.

Examples of Application Software• Word Processing Software is used to write letters, reports

and other documents. Microsoft Word is an example of such software.

• Spread Sheet is used to carryout financial, engineering, and other calculation. Microsoft Excel is and example of such software.

• Database Software is used to store information such as sales, customer, address, and inventory for future use. Microsoft Access and Oracle database are examples of such software.

• Email Software is used to send, receive, and store electronic mails. Microsoft Outlook is an example of such software.

Network

• What is a Network?• LAN vs. WAN– There are two major types of computer network: Local

Area Network (LAN) and Wide Area Network (WAN). The difference between LAN and WAN is simple. When the computers at single location are interconnected to form a network, this is a LAN. When computers at different locations are interconnected to form huge network, this is a WAN. A WAN might connect two or more LAN.

Benefits of Network• Hardware Sharing: a network lets you share expensive

hardware such as fast printer and plotter; so that not every user must have his own printer and plotter.

• Better Communication: a network enables group communication application such as email and instant messaging.

• Application Sharing: a network let you run application on server, instead of installing them on each individual computer.

• Shared Knowledge: a network lets you share important files and information between users so that each user can have updated information.

The Use of Computers in our Life

• Email

• E-Commerce

• E-Government