Download Unit A: Computer and Internet Basics

Computer and
Internet Basics
Unit A
What is a computer?
A computer is a device for
processing data. More
precisely a computer is a
device that accepts input,
processes data, stores
data, and produces output,
all according to a series of
stored instructions.
A program is a set of
instructions to perform a
task.
A Computer is a device that
accepts input
processes data
stores data
produces output
(all according to a series of stored instructions)
Computer System
Peripherals
Computer +
input devices + output devices + storage devices
Computer System
Computer system consists of:
Hardware includes the
electronic and mechanical
devices that process data.
Examples: microprocessor,
key board.
Peripheral devices expand
the computer’s input, output,
and storage capabilities.
Examples: Printers.
Software: programs
Computer Network
A computer network consists of two or more
computers and other devices that are connected
for the purpose of sharing data and programs.
LAN
A LAN (local Area network) is a
computer network that is located
within a limited geographical
area, such as a building or
campus.
COMPUTER FUNCTIONS
Computer Input is whatever is put
into a computer system.
Input can be supplied by a person,
by the environment, or by another
computer.
Data refers to the symbols that
represent facts, objects, and ideas.
COMPUTER FUNCTIONS
Computer manipulate data in many ways, and
we call this manipulation processing
COMPUTER FUNCTIONS
The instructions that tell a computer how to carry out the
processing tasks are referred to as a computer program.
In a computer most processing takes place in the central
processing unit (CPU) (also known as microprocessor)
A computer stores data so that it will be available for
processing.
Memory is an area of a computer that temporarily holds
data waiting to be processed, stored, or output.
Storage is the area of a computer that holds data on a
permanent basis when it is not immediately needed for
processing.
Computer Functions
Input
•Words, symbols, numbers, sound,
pictures, program instructions
•Program calculates, sorts modifies data
Process
•Uses microprocessor or CPU
Output
Store
•Results of processing
•Reports, graphs, documents, pictures
•Printer or monitor
•Memory is temporary holding area (RAM)
•Storage is permanent (disk)
Categorizing Computers
Cost
Usage
Size
Capability
Less Powerful Computers
•Handheld computer/PDA
•PC/microcomputer
•Workstations
•Videogame console
–Sony PlayStation®
Personal Computer
A PC is designed to meet the computing
needs of a person. It typically provides
access to a wide variety of computing
applications, such word processing, photo
editing, e-mail, etc.
There are four types: desktop, notebook
computers, workstations, and video game
console.
Workstations are usually powerful desktop
computers for special purposes.
Servers
The purpose of a server is to serve the
computers on a network by supplying them
with data.
A PC, workstation, mainframe or
supercomputer can work as a server.
Mainframes
A mainframe is a large and expensive
computer capable of simultaneously
processing data for hundreds or
thousands of users.
Mainframes are used by businesses,
universities, or governments to provide
centralize storage, processing and
management of large amount of data.
Supercomputers
A computer is a supercomputer
if, at the time of construction, it
is one of the fastest computers
in the world.
Supercomputers are used in
complex tasks such as breaking
codes or climate modeling.
The CPU of a supercomputer
contains thousands of
microprocessors.
http://www.top500.org
Computer System
Peripherals
Computer +
input devices + output devices + storage devices
System Unit
The system unit is the case that
holds the power supply, storage
devices, and the circuit boards,
including the main circuit board (also
called the “mother board”), which
contains the microprocessor.
System Unit
Power Supply
Storage Devices
Circuit Boards
Input/Output Devices
Monitor
Keyboard
Mouse
Modem
Printer
Speakers/sound card
Notes
You can use a modem to establish an
Internet connection using an
standard telephone line.
Computers have many types of
storage devices that are used to
store data when the power is turned
off.
Storage Devices
Floppy disk drive
Hard disk drive
CD-ROM drive
DVD drive
CD writer
Storage Devices
A floppy disk drive is a storage device that reads
data from and writes data to a floppy disks.
A hard disk drive can store billions of characters of
data.
A CD-ROM drive is a storage device that uses
that uses laser technology to read data that is
permanently stored on data or audio CDs.
A DVD drive can read data from CDs DVDs, or
DVD movie discs.
Data vs. Information
Data (symbols) used by computers
Information (meaningful) used by people
Data
Computers process and store data using the
binary number system and several other codes
designed expressly for electronic data.
Binary number system has only two digits 0 and
1.
Each 0 and 1 is a Bit.
Byte (8 bits)
Files
Collection of data on a storage
medium
Data file (passive)
Executable file (active)
Filename and extension
Image.jpg
Word.exe
Resume.doc
Software
Application Software is a set of
computer programs that helps a
person carry out a task.
System Software is a set of
computer programs that helps a
computer carry out basic tasks.
System Software
Helps the computer monitor itself
in order to function efficiently
Operating system
– Master controller of all computer
activities
Popular operating systems
– PCs: Microsoft Windows, Mac OS
– Handhelds: Windows CE and Palm OS
– Servers: Linux and UNIX
Computers that operate in essentially the
same way are said to be compatible.
Two of the most important factors that
influence the compatibility of two
computers are the microprocessor and the
operating system.
A platform consists of the underlying
hardware and software of the computer
system.
Platform
Microprocessor + Operating system
Mac and PC compatibility is an
issue
Apple computer = Mac platform
Original IBM computer =
Windows or PC platform
Application Software
Microsoft
Microsoft
PowerPoint
Excel
Designed
to carry out
a particular
task
Internet Basics (Cyberspace)
Internet is a
collection of local,
regional, national
and international
computer networks
that are linked
together to
exchange data and
distribute
processing tasks.
Internet Terminology
The Internet backbone defines main Internet
routes
route= telecommunication link
– Constructed and maintained by major
telecommunications companies.
TCP/IP is a standard set of rules for
electronically addressing and transmitting data.
– Transmission Control Protocol/ Internet
Protocol
Internet Backbone
Internet Terminology
IP Address: unique
number for each
Internet computer
Packets: small chunks
of data ready to travel
the Internet
Router: helps send
along the packets to
correct destination
Internet Resources
Internet Telephony
Usenet
E-commerce
Instant Messaging
Web Sites
E-mail
Internet Radio
Download Or Upload
Chat Groups
Modem Internet Connections
Dial-up connection via modem requires a modem,
which converts your computer’s digital signals into a
type of signal that can travel over phone lines.
The maximum speed is 56Kbps, or 56,000 bits per
second.
E-mail, E-commerce, and chat.
Faster Internet Connections
ISDN (Integrated Services Digital
Network) provides data transfer speeds of
either 64K or 128K.
– Always-on and expensive
DSL (Digital Subscriber Line) is a generic
name for a family of high –speed Internet
links, including ADSL, SDSL, and DSL
lite.
– Up to 125 times faster than dialup
Both ISDN and DSL connections require
proximity to a telephone switching station.
Internet Service Provider (ISP)
An ISP is a company that maintains Internet
computers and telecommunications equipment
in order to provide Internet access to
businesses, organizations and individuals
User ID and password required
Email account monthly fee
Should have local access telephone numbers
World Wide Web Basics
The web (or World Wide Web) is a collection of files that are
interconnected through of hypertext.
Hypertext: text, video, pictures.
A Web pages is a collection of hypertext documents and links (or
hyperlinks).
A link is a related document.
A web site is a collection of web pages with an Internet address.
A Web server is a computer that stores and distributes web
pages.
World Wide Web Basics
URL (uniform resource locator) is the
internet address of a web site.
HTTP ( Hypertext Transfer Protocol) is the
communications standard that is used to
transport web documents over the Internet.
HTML (Hypertext Markup Language) is a
language to create web pages.
– .htm or .html file extension
http://www.cnn.com/showbiz/movies.htm
Web
protocol
standard
Web
server
name
Folder
name
Document name
and filename
extension
Browsers and Search Engines
A browser is a software program that runs
on your computer and helps you access
web page.
A search engine refers to a web site that
provides a variety of tools to help you find
information on the Web.
Microsoft Internet Explorer® and Netscape Navigator®
Computer and
Internet Basics
End