Exploring Types of Computers in Information Technology

1. Module 1 IT Concepts of information technology

2. Part 1

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

4. Mainframe computer • Description 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...

5. ( 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 …..

6. Networked Computer • Description 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…..

7. Laptop • Description 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

8. 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

9. Hardware

10. Computer Components

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

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

13. 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

14. Memory

15. 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

16. 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

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

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

19. 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 .

20. Input And Output Device

21. 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

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

23. 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

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

25. Touch pad • Touch pad can be used by graphic artists

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

27. Joy stick • Used in games

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

29. 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

30. 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

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

32. Computer monitor • The VDU ( Visual Display Unit ) is the computer screen used to outputinformation.

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

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

35. Printers • Laser Printer • Color laser printer • Inkjet printers • Dot matrix printers • Plotter

36. Speakers

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

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

39. Hard disk • Internal Hard Disks • Speed: • 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

40. Hard Disks External Hard Disks • Speed: • 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.

41. DVD Drives • Speed: • 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.

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

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

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

45. 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.

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

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

48. Software Types of Software • Operating System • Application Program

49. Format • 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.

50. Operating System • 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