Computer Skills
Introduction
This course consist of three main topics:
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Computer System
1.
2.
Hardware
Software
A.
B.
3.
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user
Offices
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System Software (Ms-DOS, MS-Windows).
Application software (games, office).
Word
Excel
Power Point
Access
Outlock…..etc.
Internet
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The Computer
• Computer : is an information processing
machine used in different departments and
organizations.
• It performs three main operations:
 Receive input (data: raw facts).
 Process it according to predefined instructions.
 Produce output (information: meaningful data).
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Computer Operations
Computer
Receive
Data
Produce
Process
• Data: raw facts.
• Information: meaningful data.
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Information
Computer Components
The major components of any computer are:
• Input Devices: this group consists of devices that
enable the computer to receive (insert) data.
• System unit (CPU unit): This unit contains many
components used to process data (CPU, Memory).
• Output Devices: this group consists of devices that
translate the information processed by the computer into
a form that humans can understand (display
information).
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Hardware
• Hardware: physical components in the
computer system like Screen, Cables, Keyboard
and printer. Cannot do anything without
software.
Three main group will be studied in details:
– Central Processing Unit (CPU).
– Memory (primary && secondary).
– I/O devices.
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Central Processing Unit (CPU)
The CPU is the central electronic chip that
determines the processing power of the
computer.
 it is the brain of computer.
It interprets and executes the instruction contained
in software program (process data inside
computer).
It determines how fast your computer will run.
It is measured by MHz (Mega Hertz).
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CPU Parts
•
CPUs have three basic parts:
1.
Arithmetic and Logic Unit (ALU).
Performs arithmetic operations and logical operations and control the
speed of those operations.
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–
2.
Arithmetic operations: + , - ,* , / .
Logical operations: > , <, == , <= , >= ,<>.
Control Unit (CU).
1.
2.
3.
Tells the rest of computer system how to carry out a program’s
instructions.
It directs the movement of electronic signals between main
memory and the arithmetic unit.
It directs the electronic signals between main memory and the
input and output devices.
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CPU Parts
3. Registers or Immediate Access Memory.
This is a high access memory used to immediately store:
A.
B.
Data that is used by the ALU.
Program instructions which are used by the Control Unit.
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Memory
• The computer stores data and information
into special places called memory, this
memory enables the user to get his data
whenever he want.
• There are two main types of memory:
– Primary memory.
– Secondary memory.
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Primary Memory
• Forms of Primary Memory (Primary Storage) are:
– RAM. Random Access Memory
• The location where data and programs are stored.
• Volatile : the data is only there while the power to the computer is
turned on.
• It is comprised of chips attached to the motherboard.
• It’s speed measured in Megahertz (MHs).
• It’s size 16, 32,64 or 128 Megabyte.
– ROM. Read Only Memory
• This a very small capacity main memory.
• It keeps instructions which make the computer work when turning it
on.
• Its not volatile.
• The computer cannot write on it.
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─ Cache Memory.
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•
•
•
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It is linked to the CPU.
It has very fast chips.
Keep frequently used programs and data.
It helps to increase the speed of the computer.
It reduces the gap speed between the RAM and the CPU.
─ Flash Memory.
• Memory that is divided into blocks, so it saves and erased data in
faster way.
• It is a non volatile memory.
• Can be used to:
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To save BIOS in computers.
In mobiles.
In portables.
In digital camera.
Printers.
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Secondary Memory
Also called:
• Storage Devices.
• Secondary Storage System.
• External Storage.
This memory is used to keep software,
programs and data permanently.
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Secondary Memory Types
• Hard Disk
– Located within the CPU. (high speed & non portable).
– Capacity 20 GB or more. (high capacity).
• Floppy Disk
– Small disk with low speed and portable.
– Capacity 1.4 MB.
• CD-ROM (Compact Disk Read Only Memory)
– It is an optical disk (uses laser to read the information).
– High speed memory (less than Hard Disk).
– Capacity 700 MB.
• DVD (Digital Versatile Disk).
– High capacity development of CD-ROM.
– Capacity (4.7-17) GB.
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Secondary Memory Types
• Zip Disc
– It is similar to floppy disks shape. (just heavier).
– Its capacity (100-750)MB.
• Magnetic Tape
It is made of flexible plastic coated on one side with a magnetic
material.
It is used to store backup data.
• Smart Card
It look like credit card but contains a microprocessor and
memory.
• USB Flash Drives
– Easy to use.
– Complete freedom and mobility.
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Data Representation in the Memory
• Bit : 1 or 0 (binary form).
• Nibble: 4 bits (a half of byte).
• Byte: A group of 8 Bits.
Memory unit represent 1 character.
it is used to measure the memory capacity.
•
Kilobytes(KB):about 1000 byte exactly it is1024 Bytes.
•
Megabyte(MB):about 1 million byte exactly it is1024x1024 Bytes.
•
Gigabyte(GB): about 1 billion byte exactly it is1024x1024x1024 Bytes.
•
Terabyte(TB): about 1 trillion byte exactly it is 1024x1024x1024x1024
Bytes.
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Input /Output Devices
• Input Devices: allow you to input (insert)
information to the computer.
• Output Devices: allow you to output
(display or print) information from the
computer.
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Input Devices
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Keyboard
Mouse
Trackball
Touch Pad
Light Pen
Scanners
Bar Codes
• Optical Marker
Reader (OMR)
• Magnetic Strip
• Joystick
• Microphone
• Digital Camera
• Video Camera
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Output Devices
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Monitors: Video Display Units (VDU).
Plotters
Speakers
Speech Synthesizers
Projectors
Printers
Data Show
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Types of Monitors
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Cathode Ray Tube (CRT): (Traditional screen):
– It is like Television screen but more clear.
– It is less cost and less safety than Flat one.
• Flat-Panel Display
– It is Flat screen like Liquid Crystal Display (LCD).
– It is more expensive and more safety than CRT.
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Characteristics of monitors:
1.
Color: depends on the construction of the monitor and the graphic
adapter.
2.
3.
Size: (diagonally) “15- 17”inch,”19- 21”.
Resolution: the number of displayed pixels on the screen.
High resolution means clearer display.
VGA
:
640 x 480
SVGA
:
800 x 600
XVGA
:
1024 x 768
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Printers
Printers: are devices that converts
computer output into printed papers.
Hard copy: refers to printed output.
Software copy: refers to output that is in
the form of sound or displayed on a
computer screen.
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Kinds of Printers:
• Laser: use Laser beam source to print documents. It is high quality,
robust printer, high speed and high expensive especially the colored one.
• Inkjet: spray one or more colors of small droplets of ink at high speed onto
paper. It is less quality, robust, speed and expensive than Laser one.
• Dot Matrix: use pins to strike on an inked ribbon against paper. It is less
quality, robust, speed and expensive than Inkjet.
• Daisy Wheel: characters are raised on a wheel, which strikes the ribbon
placed between them, and the paper. It is an impact, which is both slow and
noisy.
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it produces carbon copies.
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Input/Output Device
• TouchScreen: this device is both input/output;
this device is a video display screen that has
been sensitized to receive input from touch of a
finger.
• Storage Devices :can be input Devices or
output Devices depending on the way they are
used.
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Types of Computers
According to their capacity and
performance, computers are classified
into seven categories:
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Types of Computers
1.
Super Computers.
High capacity, very expensive. Usually used for research.
2.
Mainframes.
Room-sized, expensive, high speed, very powerful, large storage capacities.
It is used in large organizations like Banks and government departments.
It is connected to a set of terminals that could be dumb-terminals or intelligentterminals.
3.
Mini Computers.
Do the same jobs as a mainframe, but on a smaller scale.
4.
Personal Computers (PCs)
It is small computer which has its own system (CPU, Memory, Harddisk … etc.).
It is not expensive and very popular.
It can be set on a disk.
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Types of Computers
5. Laptop Computers.
It is small, briefcase-sized and portable.
It has small screen and small keyboard.
It is as powerful as PC but more expensive than it.
6. Palmtop Computers.
It is a hand-held computer, which is called Notepad.
It has a small screen and keyboard.
Most of it’s functions are done by using pen.
It is very cheap.
7. Network Computers.
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Network Computer NC
A set of computers that are connected together and
share data (Data-sharing) and resources (Resourcesharing). Two main types of these computers:
1. A set of connected PCs that can be work
independently and can share data and resources.
(peer-to-peer network).
2. A large Computer (Server) that is connected to
other computers (Clients). (client-server network).
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Computer Performance
1- Clock Speed: Faster clock speed means more operations can be
executed per second.
2- Memory Capacity: larger number of RAMs means Faster computer.
Because if the memory does not have enough space, the computer will have
to use a part of hard disk (slower than Ram) as a virtual memory.
3- Hard Disk Speed: less access time means faster hard disk and
computer.
4- Bus Speed: Bus transfers data, instructions, controls and signals
between computer parts. So faster bus means faster computers.
5- Graphics Acceleration (GA): if the computer have GA its
performance will be better as it can display result in faster and clearer way,
if this GA has its own memory and CPU, the computer will be more faster.
6- Cash Memory: Computer with cash is faster than one without cash.
7- The Number of Running Applications.
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Software
• Software: is a set of programs, data, and
information.
• Program: is a set of sequence instructions
that tell the computer what to do.
• Hardware cannot work without software.
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Software
Software
Application Software
(Programs)
System Software
(Operating system)
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System Software
• It is special type of program that loads
automatically when you start your
computer.
• Dos: Provides non Graphical User Interfaces (GUIs). It
provides only Blank screen to type the command(s).
• Windows: Provides Graphical User Interfaces
(GUIs) such as Menu, Commands, List Box, Tools … etc.
So it depends on using mouse.
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Application Software
All applications (programs) that may be installed in the
computer system if the user want them.
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Word processing (WinWord)
Spreadsheet (Excel)
database (Access)
Presentation (PowerPoint)
Web Designer (Front Page)
Games (Fifa2000)
Multimedia (Encarta)
Desktop Publication (Adobe Photoshope)
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Computer Uses
• The computer is used in everyday life.
– Banking
– Medicine
– Accounting
– Airline Reservation
– ……..
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The END of introduction part.
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