1. Computer Skills Week – 2 (30/08/2015 – 03/09/2015) Dr. M. Ammad uddin
IT Concepts
Computer Skills
Week – 2
(30/08/2015 – 03/09/2015)
Dr. M. Ammad uddin

2. What is a computer?
A computer is a digital device which can be programmed to change (process) information from one form to another.
Do exactly as they are told.
Digital devices: Understand only two different states (OFF and ON - 0 and 1)
Instructor: Dr. M. Ammad uddin 2 2

3. General purpose computers Super computer Mainframe Medium Computer
Types of Computers
General purpose computers
Super computer
Mainframe
Medium Computer
Micro-Computer
Workstations
Control Computer
Instructor: Dr. M. Ammad uddin 3 3

4. Types of computers: Super computers Large storage capacity
Fast processing power
Can be connected to hundred of terminal units
Used by NASA, Saudi Aramco and similar organizations
Example: CRAY supercomputers
Instructor: Dr. M. Ammad uddin

5. Types of Computers: Mainframe Computers
Used by large businesses, universities and communication companies
Typically supported thousands of users
Very expensive
Used for very large processing tasks
IBM’s new Mainframe
Instructor: Dr. M. Ammad uddin 5 5

6. Types of Computers: Medium Computers
No more used these days (obselete)
Mini-Computers have replaced this type of computers
Instructor: Dr. M. Ammad uddin 6 6

7. Types of Computers: Micro-Computers
Also known as Personal Computers
Small, self-contained computers with their own CPUs
Uses a microprocessor, a CPU (Central Processing Unit) on a single chip.
Instructor: Dr. M. Ammad uddin 7 7

8. Micro-Computers Desktop computers Laptop computers Tablets Wearables 8
Instructor: Dr. M. Ammad uddin 8 8

9. Types of Computers: Workstations
Similar to Micro-Computer as being used by only one person.
More powerful in terms of
Processor capabilities
Storage capacity
Graphics capability
Used by scientists and engineers to manage applications
Instructor: Dr. M. Ammad uddin 9 9

10. Types of Computers: Control Computers Used in real time applications
Found in control rooms of power stations, petroleum refineries and train stations
Can deal with errors and repairing errors effectively
Instructor: Dr. M. Ammad uddin 10 10

11. Hardware versus Software
Hardware = The physical components that make up a computer system.
Instructor: Dr. M. Ammad uddin 11 11

12. Hardware versus Software
Software = The programs (instructions) that tell the computer what to do.
System Software
Application Software
Stored on a storage media such as hard disk, CD-ROM, floppy disk, tape, etc.
Instructor: Dr. M. Ammad uddin 12 12

13. Hardware Components Know these! PROCESS 13
Instructor: Dr. M. Ammad uddin 13 13

14. 1- The Processor Let’s open the box! 14 Instructor: Dr. M. Ammad uddin

15. 1- The Processor
circuit board = a board with integrated circuits (microchips)
system board or motherboard
interface boards or expansion boards
system board or motherboard = a single circuit board with the components which make up the computer’s processor for a microcomputer, including the:
CPU (Central Processing Unit)
Memory
RAM
ROM or ROM BIOS
expansion slots
Instructor: Dr. M. Ammad uddin 15 15

16. 1- The Processor: The CPU
CPU (Central Processing Unit) = A complex collection of electronic circuits on one or more integrated circuits (chips) which:
executes the instructions in a software program
communicates with other parts of the computer system, especially RAM and input devices
The CPU is the computer!
Rick Graziani
Instructor: Dr. M. Ammad uddin 16 16

17. 2- Memory Unit
Memory = A collection of electronic circuits which are used to save data and software programs.
There are two kinds of memories:
Random Access Memory (RAM)
Read Only Memory (ROM)
Instructor: Dr. M. Ammad uddin 17 17

18. 2- Memory Unit: RAM RAM is TEMPORARY memory RAM is volatile
stores ON and OFF bits (software and data) electrically
when power goes off, everything in RAM is lost
Instructor: Dr. M. Ammad uddin 18 18

19. 2- Memory Unit: ROM (Read Only Memory)
ROM (Read Only Memory) = integrated circuits (microchips) that are used to permanently store start-up (boot) instructions and other critical information
Read Only = information which:
Cannot be changed
Cannot be removed
Fixed by manufacturer
Instructor: Dr. M. Ammad uddin 19 19

20. 2- ROM (Read Only Memory)
ROM is sometimes known as ROM BIOS (Basic Input Output System software)
ROM contains:
start-up (boot) instructions
instructions to do “low level” processing of input and output devices, such as the communications with the keyboard and the monitor
Instructor: Dr. M. Ammad uddin 20 20

21. 3- Input Units
An input device is any hardware component that allows you to enter data and instructions onto a computer.
This data can be in the form of:
Text
Signals
Pictures
Audios
Instructor: Dr. M. Ammad uddin 21 21

22. Input Devices: Giving Commands
Keyboard
Mouse
Other Pointing Devices
Instructor: Dr. M. Ammad uddin

23. Alternative Input Devices
Fax Machines
Scanners
Flatbed
Barcode reader
Instructor: Dr. M. Ammad uddin

24. Scanners
Used to insert the replicas of pictures and documents into the computer.
Can be used through proper software developed for such purposes.
Instructor: Dr. M. Ammad uddin

25. Microphones Used to input the voice commands and communication.
Instructor: Dr. M. Ammad uddin

26. 4- Output Units
Instructor: Dr. M. Ammad uddin 32 32

27. Output Devices: Engaging our Senses
Output devices are peripheral devices that enable us to view or hear the computer’s processed data.
Visual output – Text, graphics, and video
Audio output – Sounds, music, and synthesized speech
Instructor: Dr. M. Ammad uddin

28. Monitors
CRT
LCD
A monitor is a peripheral device which displays computer output on a screen.
Screen output is referred to as soft copy.
Types of monitors:
Cathode-ray tube (CRT)
Liquid Crystal Display (LCD or flat-panel)
Instructor: Dr. M. Ammad uddin

29. Monitor Specifications
Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21)
Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200)
Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)
Instructor: Dr. M. Ammad uddin

30. Printers
A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
Instructor: Dr. M. Ammad uddin

31. Types of Printers
Laser
Inkjet
Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper
Letter-quality printouts
Cost of printer is inexpensive but ink is costly
Laser printer works like a copier
Quality determined by dots per inch (dpi) produced
Color printers available
Expensive initial costs but cheaper to operate per page
Instructor: Dr. M. Ammad uddin

32. Plotter
A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.
It is used in engineering, drafting, map making, and seismology.
Instructor: Dr. M. Ammad uddin

33. Audio Output: Sound Cards and Speakers
Audio output is the ability of the computer to output sound.
Two components are needed:
Sound card – Plays contents of digitized recordings
Speakers – Attach to sound card
Click an icon to play music.
Click the icon again to stop playing.
Try clicking on Cheers while playing music.
WMA
MIDI
MP3
WAV
Beethoven 1:15 min
Rocky 2:56 min
Hornsby 48 sec
Cheers 15 sec
Instructor: Dr. M. Ammad uddin

34. Memory vs. Storage
RAM – memory
Hard Drive – storage
Storage, also known as mass media or auxiliary storage, refers to the various media on which a computer system can store data.
Storage devices hold programs and data in units called files.
Memory is a temporary workplace where the computer transfers the contents of a file while it is being used.
Instructor: Dr. M. Ammad uddin

35. Why Is Storage Necessary?
Storage devices:
Retain data when the computer is turned off
Are cheaper than memory
Play an important role during startup
Are needed for output
Instructor: Dr. M. Ammad uddin

36. Storage devices are categorized by:
The type of operations they perform
The method they use to access the information
The technology they use
Their location in the storage hierarchy
Their capacity and speed
Instructor: Dr. M. Ammad uddin

37. Sequential vs. Random Access Storage
Hard Disk – random-access storage
Tape Drive – sequential storage
Floppy Disk Drive – random-access storage
Sequential – Storage devices that read and write data in a serial (one after the other) fashion
Random-Access – Storage devices that read and write data without going through a sequence of locations
Instructor: Dr. M. Ammad uddin

38. Storage Technologies: Magnetic and Optical
Optical Storage – CD/DVD drive
Magnetic Storage
Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material
Optical – Storage devices that use laser beams to read patterns etched into plastic disks
Instructor: Dr. M. Ammad uddin

39. The Storage Hierarchy The three levels of storage hierarchy are:
Online storage – Also called primary storage, it is made up of the storage devices that are actively available to the computer system. User action is not required.
Near-online storage – Also called secondary storage, it is not readily available to the computer system. The user performs an action, such as inserting a disk, to make it available.
Offline storage – Also called tertiary storage or archival storage, it is not readily available to the computer system. Devices such as tape backup units store data for archival purposes.
Instructor: Dr. M. Ammad uddin

40. Storage Capacity and Speed
Floppy Disk
Hard Drive
CD ROM / DVD
Capacity – CD-ROM 650 MB; DVD 17 GB
Access Time – 80 to 800ms
Capacity – 720 KB to 1.44 MB
Access Time – 100ms
Capacity – Up to 80 GB
Access Time – 6 to 12ms
A storage device’s performance is measured by:
Capacity – The number of bytes of data that a device can hold
Access Time – The amount of time, in milliseconds (ms), it takes the device to begin reading data
Instructor: Dr. M. Ammad uddin

41. Hard Disks Hard disks are high-speed, high-capacity storage devices.
Platter
Read/Write head
Hard disks are high-speed, high-capacity storage devices.
They contain metal disks called platters.
They contain two or more stacked platters with read/write heads for each side.
Hard disks can be divided into partitions to enable computers to work with more than one operating system.
Instructor: Dr. M. Ammad uddin

42. Floppy and Zip Disks and Drives
Zip Drive
Floppy Drive
Click on the picture to see it work.
Floppy Disk
A disk or diskette is a portable storage medium.
High-density floppy disks that are commonly used today store 1.44 MB of data.
Disks work with a disk drive.
Zip disks store up to 750 MB of data and are not downwardly compatible with floppy disks.
Instructor: Dr. M. Ammad uddin

43. CD-ROM Discs and Drives
CD-ROM stands for Compact Disc-Read Only Memory.
CD-ROM drives can not write data to discs.
They are capable of storing 650 MB of data.
They are used for storing operating systems, large application programs, and multimedia programs.
Instructor: Dr. M. Ammad uddin

44. CD-R and CD-RW Discs and Recorders
Discs can be read and written to
Discs can only be written to “once”
CD-R drives are capable of reading and writing data
CD-RW
Discs can be read and written to
Discs are erasable
Discs can be written to many times
CD-RW drives are capable of reading, writing, and erasing data
Instructor: Dr. M. Ammad uddin

45. DVD-ROM Discs and Drives
DVD stands for Digital Video Disc.
DVD technology is similar to CD-ROM technology.
DVDs are capable of storing up to 17GB of data.
The data transfer rate of DVD drives is comparable to that of hard disk drives.
DVD-R and DVD-RW drives have the ability to read/write data.
Instructor: Dr. M. Ammad uddin

46. Solid State Storage Devices
Solid state storage devices use nonvolatile memory chips to retain data.
They do not have moving parts.
They are small, lightweight, reliable, and portable.
Instructor: Dr. M. Ammad uddin

47. Solid State Storage Devices
Smart Card
Memory Stick
Compact Flash Memory
Flash Memory
PC Card
Micro Drive
Instructor: Dr. M. Ammad uddin

48. Computer Performance:
CPU speed (and type)
Amount of RAM (and speed)
Hard disk capacity
Instructor: Dr. M. Ammad uddin 58 58

49. Summary
Input is the software, data, and information that is entered into the computer’s memory.
Input devices such as the keyboard, mouse, and trackball enable the user to enter data.
A pointing device enables the user to control movements of an on-screen pointer.
Speech recognition software enables the user to enter data into a computer by speaking into a microphone.
Video and images can be entered into a computer by way of digital cameras, scanners, and fax modems.
Monitors enable the user to view the computer’s processed data. The output is known as soft copy.
Instructor: Dr. M. Ammad uddin

50. Summary The two types of monitors are the CRT and the LCD.
A monitor’s quality is measured by screen size, resolution, and refresh rate.
Printers produce permanent versions (hard copies) of the computer’s output.
The two basic types of printers are the inkjet and laser.
Memory makes software and data available for the CPU’s use.
Storage devices are categorized by:
Data access (sequential or random-access)
Technology (magnetic, optical, or solid state)
Hierarchy (online, near-online, or offline)
Operations (read-only or read/write)
Instructor: Dr. M. Ammad uddin

51. Summary
A hard disk’s performance is measured by its positioning performance and transfer rate.
Optical storage devices include:
CD-ROM– Read-only
CD-R– Record once
CD-RW– Erasable, write repeatedly
DVD-ROM– Read-only
DVD-R– Read/write
Solid state storage devices include:
PC cards
Flash memory cards
Smart cards
Instructor: Dr. M. Ammad uddin