This document provides an overview of computer skills and components. It discusses [1] what a computer is and its basic functions of input, processing, and output. [2] It then explains the components of a computer system including hardware, software, and users. [3] The document delves into the various hardware components that make up a computer system such as the CPU, memory, storage, and input/output devices.

1. Prince Fahad Bin Sultan National University
Computer Skills
2011-2012
1

2. Computer
Is a machine that changes information from one
form to another, all computers takes-in information
(input) and gives-out information (output).
Input (Data) Processing Output (information)
What is Information Technology (IT) ?
A set of tools that are used to: receive , process, store,
retrieve , print and transmit information in an electronic
form through computers. these forms can be : text,
sound, picture or video.
2

3. The Components of Computer
System Are :
1. Hardware
2. Software
3. Users
3

4. 1 - Hardware
The physical parts of the computer system.
(Central Processing Unit CPU, Memory, storage
devices, Input/output). The hardware cannot do any thing without
software
1. CPU : the computer brain, it process information, performing
arithmetic calculations and make basic decision by comparing
information values. Its speed measured in Hertz
2. Memory : (Main memory) is used to store programs and
data that need to be instantly accessible to the CPU. (E.g.
RAM, ROM)
4

5. 1- Hardware
3. Storage Devices : (Secondary memory) it includes disk and tape
drives, serves as long-term repositories for data. (It serves as Input
and output devices) (E.g. CD, Floppy A , Hard-desk, Flash memory)
4. Peripherals : Any hardware that is connected to a computer .
(e.g. Printer, Scanner, Modems … )
5

6. 1- Hardware
CPU
Hard Disk RAM
6

7. 1- Hardware
Motherboard
Sound Card
7

8. 1- Hardware (I/O)
Sound_blaster
mouse
Keyboard
Microphone
Printer
scanner
Track Ball
Joystick
Camera Printer & scanner 8

9. 1- Hardware (I/O)
 Input Devices
 Keyboard
 Mouse
 Track ball
 Touch bad
 Touch Screen
 Light Pen
 Scanner (FlatBed, SheetFed, HandHeld)
 Joystick
 Microphone
 Disk Drives (DVD, CD-ROM, Floppy Disks)
 Digital and Video Camera
9

10. 1- Hardware (I/O)
 Output devices
 Video Display unit (monitor) . Resolution: The number of dots or
pixels that can be displayed on the screen. High resolution means
better quality and clearer display
 VGA = 640 * 480
 SVGA = 600 * 800
 XVGA = 768 * 1024
 Panel Display Flat
 Printers (Daisy wheel, Dot Matrix, Inkjet, Laser Printer, Plotters) .
 Speakers
 Speech Synthesizers
 Removable Media
 Projectors
10

11. 2- Software
The instructions that tell the Hardware how to
transform the input data into necessary output.
There are two General types of computer software:
1- System Software: which coordinates the Hardware
operations and does behind the scene work, the computer user
seldom sees. (Windows, dos, Mac, Unix, programming languages).
2- Application Software: which serves as productivity tools
to help computer users to solve problems. (Word, Excel, Power
Point, games, calculator ,…)
11

12. 2- Software
Software types based on the source:
1. Commercial Software: for sale software
2. Shareware Software: for sale software but with a tryout period
3. Freeware Software: free software without source code
4. Public Domain Software: free software with the source code
12

13. 2- Software
Software Interface:
1. Command Line Interface: using a keyboard only to type the
commands as a line of text.
2. Graphical User Interface (GUI): using mouse or keyboard to
select the commands as a buttons, pictures, menus … “much simpler”
13

14. 3 - Users
Are people who use the software on
the computer to do some tasks.
14

15. Data representation in the memory
Information
It can be applied to anything that can be communicated,
whether it has a value or not. (Words, Numbers, Pictures, Symbols,
Sounds, Moving Pictures).
Bit (Binary digiT)
is the smallest unit of the information. A Bit can have one of
two values. (Yes & No, Zero & One, On & OFF, High & Low).
ASCII:
American Standard Code for Information Interchange.
15

16. Data representation in the memory
Collection of 8 bits, called a byte.
• Bit 0,1
• Byte 8 bits (one letter)
• Kbyte 1024 Bytes
• Mega Byte Million Bytes
• Giga Byte Billion Byte
• Tera Byte Thousand Billion Byte
16

17. Computer Performance
Clock Speed: It is the number of cycles that the
CPU(Processor) can do per one second
MHz :It is a unit to measure the speed of CPU.
e.g.
33 MHz
33 million cycles in one second.
17

18. Cycle (Access Time)
The Time that the processor needs to retrieve
data from memory.
• Hard disk (secondary memory): the access time can
be measured in Millisecond (thousandths of second)
(1/1000 of second).
• RAM and ROM (Primary memory): the access time
can be measured in Nanosecond (Billionths of second)
(1/1000000000 of second).
18

19. CPU ( Central Processing Unit )
ALU
Consists >> Register
CU
1 - ALU: Arithmetic Logic Unit.
- It performs the arithmetic (+, -, / ,*, .. ) and logic
(And, Or, Not, >, <, <=, …) operations.
- It consists of:
1) ICs (integrated Circuits)
2) Registers: to store intermediate results.
19

20. CPU ( Central Processing Unit )
2 - CU: Control Unit:
It send commands (instructions) to all computer
parts (ALU, Memory, I/O) to manage computer tasks.
33 - Buses:
TThere are three kinds of Buses at the CPU: ALU
 Address Buses. Register
 Data Buses.
CU
 Control Buses.
20

21. Memories (Main Memory)
1. RAM (Random Access Memory) (Volatile) Memory that can be read
from or write to by a computer or other devices. Information
stored in RAM is lost when you turn off the computer.
2. Cache memory (Volatile) Faster than RAM, It’s used to store the data
and instructions that need to be retrieved many times. (The most
recently used data)
3. ROM ( Read Only Memory ) (nonvolatile) It is used to read instructions
only (not to write). It contains the start-up instructions, which was
etched-in when the chip was manufactured.
4. Registers (Volatile) It is an electronic unit can be used to store very tiny
amount of information (Intermediate information). It is located at
ALU and CU normally.
21

22. Memories (Secondary Memory)
1. Flash memory (nonvolatile) Faster than RAM, it can be used also in Mobiles,
Digital camera and printer.
2. Magnetic Tape (nonvolatile) Like cassette.
3. Hard Disk (nonvolatile) : it’s the most important storage media in the computer
4. Floppy Disks (nonvolatile) : 1.4 MB
5. CD-ROM (nonvolatile) : 700 MB
6. Digital Versatile Disk (nonvolatile): 17 or 4.7 GB
22

23. Computer Types (Based on the Size)
1 - Mainframes:
- Large and very expensive (Size of refrigerator, cost a round a million US $)
- Used by large organizations for big computing jobs. (Banks, Airlines)
- They are connected to a large number of terminals that could be dumb
(can not operate on their own)
Terminal: a combination keyboard and screen that transfers
information to and from the computer.
Intelligent Terminals: They have processing power themselves that can be
used by the user.
Characteristics:
• It gives more mathematical computing power than PCs.
• It lets the users share expensive computing equipments.
• Save memory space.
23

24. Computer Types (Based on the Size)
2 - Supercomputers
* Most powerful computers.
* The fastest (1.6 trillion operation per second)
* It is called sometime High Performance Computer.
* Used in large scientific and research laboratories, space
operations
3 - Minicomputers
* Multi-user machine.
* Smaller and less expensive than mainframes, but larger
and more expensive than PCs.
* Minicomputers are history. (Not produced today)
24

25. Computer Types (Based on the Size)
4 - PCs (Microcomputers):
The Personal Computer can be any general-purpose,
single-user computer.
It consists of: ( System Unit, Monitor, Keyboard, Mouse)
5 - Portable computers:
* Laptop computers.
* Notebook computers.
25

26. Computer Types (Based on the Size)
Portable
Mainframe
Supercomputer
26

27. Computer Types
(Based on the processing method)
1) Digital Computers: are used to process all discrete data.
(Digits, Letters)
2) Analog Computers: are used to process the connected
data. (Temperature, Speed, atmospheric pressure)
3) Hybrid computers: for all data (discrete and connected
data), the internal processing is digital.
Computer characteristics:
* High speed in performing Operations. (thousand million operation per second)
* It gives very accurate results.
* It used to store very big amount of information.
* Multiple uses.
27

28. Operating Systems (OS)
 It is a collection of programs and instructions, which
it is main function is to manage the computer
resources and to organize using it. (Resources: I/O,
Programs, and Secondary storage devices like magnetic tapes.)
Functions
 Make sure of I/O operations.
 Manage the stored information in the memory.
 Protect computer users from each other.
 Provide the connection with other computers.
 Keep the computer system in secure
28

29. Operating Systems (OS) Continued …
Types of OS:
1. Multi-users (Network OS)
Allow many users to use the computer at the same
time. it uses the timesharing property
2. Multi-tasks:
The ability to perform many tasks at the same time.
3. Open-system:
The ability to use the OS over different devices.
4. Multiprocessor:
29

30. Programming Languages
A set of words, rules, syntax and semantic used by a programmer
to input his instruction to the computer to solve some problems or to do
specific task. Computers can understand these languages.
Compiler or Interpreter: is a translator that translates the programming
languages to the machine language that the computer can understand. A
Compiler translates whole program at once but the Interpreter translates
one instruction at a time
Programming languages have to levels :
1- Low-Level Languages
* Machine language
* Assembly Language
2- High-Level-Language
30

31. Programming Languages Continued …
1 – Low Level Languages ( LLL ):
 Machine Language:
Is the only language that the computer can understand without
translation.
 It consists of (0, 1).
 Very fast (in execution).
 Each computer has its own machine language.
 Very difficult ( because the programmer should know his computer
very-well )
 Assembly Language:
Relatively, its more developed and easer than machine
language.
 It considers as intermediary language between machine
 language and High-level languages.
 It allows you to use letters and digits instead of (0, 1).
31

32. Programming Languages Continued …
2 – High Level Languages (HLL):
Its more developed and close to the human languages.
 Easy to use and to write programs.
 Easy to discover the errors and to fix it.
 It saves the time and the efforts.
 Easy to deal with computers.
 Portable: the program that designed for special
computer can be executed in other
computers, which are differ in its version.
Examples: Fortran, Cobol, Basic, Pascal, C.
32

33. Multimedia
 Is the use of different media in computer
programs:
 Text
 Graphics
 Audio
 Video
 Animation
 Its used in
 Presentation
 Education
 Learning
 games
33

34. Data Communication & Networks
 The Benefits of this technique are:
 Sharing of files, documents and resources
 Sharing Software
 Sharing Equipments
 Sending messages to all people on the network
 Providing Services efficiently (E-government)
34

35. NETWORKS
1- Local Area Network (LAN)
It’s a network designed to span short distances and relatively
small number of computers, usually a LAN connects the
machines in only one building or in a single room.
• Client Server Architecture
The server saves all common files and documentations so that
other computers (client) can use them
• Peer-to-Peer network
No servers, all computers have same level they share data directly
with others.
2- Wide Area Network (WAN)
It’s a network that connects two or more LANs over a large area
using satellite communications. ( e.g. Bank ATM, Internet)
35

36. NETWORKS
2- Wide Area Network (WAN)
It’s a network that connects two or more LANs over a large area
using satellite communications. ( e.g. Bank ATM, Internet)
WAN Devices :
1. HUB: to connect a lot of commuters together
2. Switcher: like a hub but it transmits data directly to it’s destination
3. Router: connects two LANs together, for large distance
4. Gateway: to connect two different OS LANs, for short distance
5. Bridge: to connect two LANs with the same OS, for short distance
6. Repeater : Repeat signals that travels via long distance
7. Multipliers: high speed path for messages
36

37. NETWORKS
Networks Topologies:
1. Star Network
• All computers connected to central computer by a hub
• If the central computer is broken the network stop working
2. Ring Network
• All Computers connected on a ring shape
• No central computer
• More expensive that Star network
• Used for Peer-To-Peer network
3. Bus Network
• Needs less wires than start or ring network
• Used for Peer-To-Peer and client –server network
37

38. NETWORKS
LAN
WAN
38

39. NETWORKS
Data Communication hardware:
1. Modem
• MODulate / DEModulate
• Telephone network
• Designed for voice (Analog format)
• Used by computer to convert analog format to digital format
2. Network card
• To connect the computers with others
3. Wire Media
• Twisted pairs (e.g Phone wire, need a modem)
• Coaxial cables (e.g T.V. wire, need a Network card)
• Fiber optics (very fast and more expensive)
4. Wireless Media
• Radio waves – Microwaves -- Satellite
39

40. INTERNET
Is a WAN network that span the globe, it gives us the
capability to exchange information.
World Wide Web (WWW, or Web): Is software that
makes sharing information across a network easy.
Uniform Resources Locator ( URL ): Specifies
documents and other information on the WWW for
browser (Internet Explorer, Netscape) to obtain and display.
40

41. INTERNET
To connect to the Internet you need:
1. PC (Personal Computer)
2. Modem
3. Telephone line
4. Browser (internet software)
5. Account with Internet service provider (ISP)
Internet Services
1. Search Engines (to help you to find information)
2. E-mail (to send and receive messages over the Internet)
41

42. Computer Ethics
 Copyright
 Pay for software and register to use it
 Copyright principles
 Software should be copied only for backup.
 Sharing/lending not allowed
 Copy software through network should be
under terms of license agreement.
 Software piracy is a crime.
42

43. Computer Ethics
 Licensing
 Buying software entitle the user for license to
use it.
 Licensing agreement is a combinations of
rules.
 Two kinds of license
 Single User : install software only on one
computer
 Site License: can be install into multiple
computers, which save money.
43

44. Computer Ethics
Viruses
Types of viruses
 Worms  Time Bombs
 Do not make any damages  It makes the damage at a
 Spread quickly through network specific time
 Keep system busy
 Trojan Horse
 Can be carried onto a computer by other files to
perform its illegal objectives.
 Backdoor
44

45. Computer Ethics
 Protecting from Viruses
 Do not use floppies from unreliable sources
 Use only registered software
 Never open an E-mail attachment unless it
is from reliable source.
 Keep regular back-ups.
45