Concepts of information technology Module 1 IT Concepts of information technology

Part 1

Types of Computers Mainframe Computers PC ( Personal Computer ) Networked Computer Laptop PDA ( Personal Digital Assistant )

Mainframe computer Description Capacity : very power full computers Are big , powerful , expensive computers used by most large organization Capacity : very power full computers Speed Very Fast in processing data Costs : very expensive Users Large companies including banks...

( PC) Personal computer Description IBM invented the pc since 1981 Capacity : large hard disk Speed Fast normally measured in GHz Costs : Getting cheaper by day Users Home users , Doctors , Education …..

Networked Computer Description Capacity : large hard disk Speed Allow you to connect two or more than one computer together Capacity : large hard disk Speed Fast normally measured in GHz Costs : A pc need inexpensive card to connect to network Users Home users , Doctors , Education , any one…..

Laptop Description Capacity : Speed Costs : Small , Portable , Can run on batteries as well as main power Capacity : Large hard disk, often less powerful than PC which is equivalent in price Speed Fast normally measured in GHz – Speed specification are less than PC which is equivalent in price Costs : Exceeds when compared with PC Users Business users , People on the move , Educational user

PDA ( Personal Digital Assistant ) Description Use a special pen rather than keyboard, can store and retrieve information Capacity : Much smaller than PC Speed Much slower than PC Costs : Exceeds when compared to PC Users : Mostly Business Users

Hardware

Computer Components

System Unit The name given to Main PC box It Houses items like …. Mother Board CPU RAM CD Floppy Disk

System (Mother ) Board All items of the system unit attached to Mother board , either directly or via cable

CPU (Central Processing Unit ) IT is one of the most important components within Computer It is the brain within your Computer It performs most of the calculation within the computer It determines How fast you Computer will run It is measured by GHz 2 GHz Pentium is much faster than 1GHz Pentium

Memory

RAM ( Random Access Memory ) It’s where the operating system is loaded when you switch on your computer It’s where your application are copied to when you start application (such as word processing ) Volatile and changeable The more RAM you Have installed in you Computer is better It is measured by MB These days you will commonly find over 512 MB of Ram installed

ROM - BIOS ( Read only Memory – Basic input out put system ) It is special chip held on your computers’ mother board It contains Software which makes your computer work with your operating system It is Non volatile, unchangeable

Serial Port It is socket located at the back of your computer which enable you to connect items to the computer , such as Modem

Parallel Port It is socket located at the back of your computer which enable you to connect items to the computer , such as Modem

USB (Universal Serial Bus ) It is Relatively new item within the PC You will see one or more USB Sockets at the back of Your computer It enables you to Plug in devices such as Printer, Scanner, Digital camera .

Input And Output Device

Input Device …. Input device allow you to input Data to the computer Key board Mouse Tracks ball Touch pad Light pen Joy stick Scanner Web Cam Digital Camera

Key Board Key board is the commonest way of entering data to the computer

Mouse The mouse came into common use on PC with the introduction of Microsoft operating system (Windows) . Before this (DOS) operating system had been controlled via the keyboard

Tracker ball A tracker ball is an alternative to the mouse. A tracker ball is favorite by graphic designers.

Touch pad Touch pad can be used by graphic artists

Light pen A light pen is used to allow users to point to areas on screen and its often used to select menu

Joy stick Used in games

Scanner A scanner allows you to scan printed material and convert it into a file format which may be used within PC

Web Cam Ever since it was invented , the web has become increasingly interactive . It allows you to communicate in two ways not just text communication but also sound and video

Digital Camera A digital camera can be used in the same way of traditional camera but instead of storing images on rolls of films , the images are storing in memory housed within the camera ,this images can easily be transferred to your computer

Output Device …. Output devices allow you to output information From the computer Computer monitor Flat screen monitor Computer presentation projection device Printers speakers

Computer monitor The VDU ( Visual Display Unit ) is the computer screen used to output information.

Flat screen monitor Flat screen computer monitor have become available , these take less size on the desk and use less energy than the traditional

Computer presentation projection device It can be attached to your computer and it is useful to display presentations to group of people.

Printers Laser Printer Color laser printer Inkjet printers Dot matrix printers Plotter

Speakers

Output / Input Device …. Some devices are both input / output devices Touch screen

Storage Device Hard desk ( Internal – External ) Zip Driver Diskette CD desk DVD driver Jaz Disks Back up tape

Hard disk Internal Hard Disks Speed: Cost: Very fast! The speed of a hard disk is often measured by “RPM" speed, The smaller this number the slower the hard disk. Capacity: Enormous! Often in excess of 10 Gigabytes. A Gigabyte is equivalent to 1024 Megabytes. Cost: Getting cheaper by the day

Hard Disks External Hard Disks Speed: Capacity: Cost: Normally slower than internal disks, but more expensive, offer the same performance as internal hard disks. Capacity: Same as internal disks. Cost: More expensive than internal disks.

DVD Drives Speed: Capacity: Cost: Much faster than CD-ROM drives but not as fast as hard disks. Capacity: Up to 30 G bytes. Cost: Slightly higher than CD-ROM drives.

CD-ROM (Compact Disc) Speed: Capacity: Much slower than hard disks. Around 650 Mbytes.

Zip Disks Speed: Capacity: Slower than hard disks but ideal for backup. Capacity: 100 or 250 Megabytes.

Jaz Disks Speed: Capacity: Slower than hard disks but ideal for backup. Capacity: Around 2 Gigabytes (2048 Megabytes).

Diskettes (Floppy Disks) It can be write protected to prevent data from changes or infection of viruses. Speed: Very slow! Capacity: Normally 1.44 Mbytes. Cost: Very cheap.

Back up Tape Used to archiving the files that are not needed

Storage measurement Tera byte = 1024 Giga byte Giga byte = 1024 Mega byte Mega byte = 1024 Kilo byte Kilo byte =1024 Byte Byte = 8 Bit

Software Types of Software Operating System Application Program

Format Pre formatted disk can be used immediately to store data. Unformatted disk need operating system data written to them before they can store files. Pre formatted disk can be used immediately to store data. Full formatting completely erase the previous contents of a disk. You can purchase preformatted disk. You can reformat a used floppy disk.

Operating System DOS Windows The operating system is a special type of programs which is loaded automatically when you start your computer There are number of different types of operating system DOS Windows Unix and Linux Mac/OS

DOS IBM invented Pc Since 1981 And used DOS Operating system. This operating system was very basic. You had to be computer expert just to understand how to use computer It was not user – friendly

Windows Microsoft introduced windows which is more powerful than DOS and which is commonly used on PC today. There are numbers of different types of windows The main advantage of windows that it has a Graphical User Interface ( GUI )

Graphical User Interface ( GUI ) It is part of operating system which display windows and drop down menus The system using windows, icons to operate a computer It enables you to drive your computer by using mouse Advantage All programs look similar and when switches from a program supplied by one manufacturer to different program supplied by another manufacturer , you will find the transition very easy By GUI its easier to learn and use Application Program

Unix & Linux Are other examples of Operating Systems which may be run on PCs

Other Types of computers , Such as Manufactured by Apple have a completely different operating System called Mac/OS .

Application Software An application program is the type of program which you use when the operating system has been loaded. Can run more than one at the same time. Can be used to edit data type

Create letters, Faxes, Memos Example …. Word Processor Create letters, Faxes, Memos Spread Sheet ( Excel ) Make financial projects With Charts Database ( Access ) Sort large amount of information Presentation ( Power point ) Crate overhead projection or slides Desktop publish Producing a newspaper with complex page layout Accounts payroll ( Sage ) (Make financial projects ) large Organizations

Things to avoid Dust Drinking and eating over the key board Heat Moisture Don’t move the system while it switched on Follow the correct steps to shutdown your computer Don’t place object in the top of monitor Don’t place floppy disk near monitor . Monitor produce a strong electromagnetic

System Cycle Most project work in cycle First step ( System analysis): Analyze the need of computer user. Second Step ( Design ) Draw up the plans on how it can be implemented on a real. Third Step ( Programming ) Convert the design to actual plan. Final Step ( Testing ) Testing the software.