IT level 1

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Computer Skills

2011-2012

Prince Fahad Bin Sultan National University

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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.

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The Components of Computer System Are :

1. Hardware2. Software3. Users

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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)

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

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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 … )

1- Hardware

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1- Hardware

RAM

CPU

Hard Disk

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1- Hardware

Motherboard

Sound Card

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1- Hardware (I/O)

Track Ball

Keyboard

mouse

Joystick

Microphone

Camera

scannerPrinter

Printer & scanner

Sound_blaster

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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

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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

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2- SoftwareThe 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 ,…)

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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

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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”

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3 - Users

Are people who use the software on the computer to do some tasks.

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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.

Data representation in the memory

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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

Data representation in the memory

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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.

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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).

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ALU

CU

 Register

CPU ( Central Processing Unit )

Consists >>

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.

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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:

Address Buses. Data Buses. Control Buses.

ALU

CU

 Register

CPU ( Central Processing Unit )

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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.

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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

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Computer Types (Based on the Size)

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.

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)

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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)

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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.

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Computer Types (Based on the Size)

Supercomputer

Mainframe

Portable

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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.

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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

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 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:

Operating Systems (OS) Continued …

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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

Programming languages have to levels :1- Low-Level Languages   * Machine language       * Assembly Language   

2- High-Level-Language 

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Continued …Programming Languages1 – 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).

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Continued …Programming Languages

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.

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Multimedia Is the use of different media in computer

programs: Text Graphics Audio Video Animation

Its used in Presentation Education Learning games

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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)

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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 ArchitectureThe 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)

NETWORKS

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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 together2.Switcher: like a hub but it transmits data directly to it’s destination3.Router: connects two LANs together, for large distance4.Gateway: to connect two different OS LANs, for short distance5.Bridge: to connect two LANs with the same OS, for short distance6.Repeater : Repeat signals that travels via long distance7.Multipliers: high speed path for messages

NETWORKS

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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

NETWORKS

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NETWORKS

LAN

WAN

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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

NETWORKS

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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.

INTERNET

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To connect to the Internet you need:1.PC (Personal Computer)

2.Modem3.Telephone line

4.Browser (internet software)

5.Account with Internet service provider (ISP)

Internet Services6.Search Engines (to help you to find information)

7.E-mail (to send and receive messages over the Internet)

INTERNET

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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.

Computer Ethics

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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.

Computer Ethics

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Types of viruses Worms

Do not make any damages Spread quickly through network Keep system busy

Computer Ethics

Trojan Horse Can be carried onto a computer by other files to

perform its illegal objectives. Backdoor

Time Bombs It makes the damage at

a specific time

Viruses

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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.

Computer Ethics