Download - Computer Skills Introduction. Computer Skills1 by Maram Bani Younes This course consist of three main topics: Computer System 1.Hardware 2.Software A.System.

Computer Skills

Introduction

Computer Skills1 by Maram Bani Younes

This course consist of three main topics:

• Computer System1. Hardware2. Software

A. System Software (Ms-DOS, MS-Windows).B. Application software (games, office).

3. user

• Offices– Word– Excel– Power Point– Access– Outlock…..etc.

• Internet


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).


Computer Operations

Computer

Receive Produce

• Data: raw facts.• Information: meaningful data.

Data InformationProcess


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).


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.


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).


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.

– Arithmetic operations: + , - ,* , / .– Logical operations: > , <, == , <= , >= ,<>.

2. Control Unit (CU).1. Tells the rest of computer system how to carry out a program’s

instructions.2. It directs the movement of electronic signals between main

memory and the arithmetic unit.3. It directs the electronic signals between main memory and the

input and output devices.


CPU Parts

3. Registers or Immediate Access Memory. This is a high access memory used to immediately store:

A. Data that is used by the ALU.

B. Program instructions which are used by the Control Unit.


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.


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.


─ Cache Memory.• 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:

– To save BIOS in computers.– In mobiles.– In portables.– In digital camera.– Printers.


Secondary Memory

Also called:• Storage Devices.• Secondary Storage System.• External Storage.

This memory is used to keep software, programs and data permanently.


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.


Secondary Memory Types

• Zip Disc– It is similar to floppy disks shape. (just heavier).– Its capacity (100-750)MB.

• Magnetic TapeIt is made of flexible plastic coated on one side with a magnetic

material.It is used to store backup data.

• Smart CardIt look like credit card but contains a microprocessor and

memory.

• USB Flash Drives– Easy to use.– Complete freedom and mobility.


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.


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.


Input Devices

• Keyboard• Mouse• Trackball• Touch Pad• Light Pen• Scanners• Bar Codes

• Optical Marker Reader (OMR)

• Magnetic Strip• Joystick• Microphone• Digital Camera• Video Camera


Output Devices

• Monitors: Video Display Units (VDU).

• Plotters

• Speakers

• Speech Synthesizers

• Projectors

• Printers

• Data Show


Types of Monitors

• 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.


Characteristics of monitors:

1. Color: depends on the construction of the monitor and the graphic adapter.

2. Size: (diagonally) “15- 17”inch,”19- 21”.

3. Resolution: the number of displayed pixels on the screen.

High resolution means clearer display.VGA : 640 x 480SVGA : 800 x 600XVGA : 1024 x 768


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.


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.

– it produces carbon copies.


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.


Types of Computers

According to their capacity and performance, computers are classified into seven categories:


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 intelligent-

terminals.

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.


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.


Network Computer NC

A set of computers that are connected together and share data (Data-sharing) and resources (Resource-sharing). 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).


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.


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.


Software

A p p lica tion S o ftw are(P rogram s)

S ystem S oftw are(O p era tin g system )

S oftw are


System Software

• It is special type of program that loads automatically when you start your computer.

• Dos: Provides non Graphical User InterfacesGraphical 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.


Application Software

All applications (programs) that may be installed in the computer system if the user want them.

• Word processing (WinWord)• Spreadsheet (Excel)• database (Access)• Presentation (PowerPoint)• Web Designer (Front Page)• Games (Fifa2000)• Multimedia (Encarta)• Desktop Publication (Adobe Photoshope)


Computer Uses

• The computer is used in everyday life.– Banking– Medicine– Accounting– Airline Reservation – ……..


The END of introduction part.