Essential
Computer
Concepts
IT SKILLS -LAB
What Is a Computer?
XP
• A computer is an electronic device that accepts
data and instructions from a user, manipulates the
data according to the instructions, displays the
information in some way, and stores the
information for retrieval later
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What is a computer?
XP
• An electronic device that accepts input,
processes the data and instructions, produces
output from the processing that is useful and
meaningful and stores the results for future use.
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How Does A Computer Know What To
Do?
XP
• It must be given a detailed set of instructions that
tell it exactly what to do.
• These instructions are called a computer program,
or software.
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Characteristics Of Computer
XP
• Speed: An instruction can be executed by a
computer in a nanoseconds.
• Storage: Large volume of data can be stored in
Tapes, Hard Disks.
• Accuracy: Calculations carried out by the
processor are generally accurate
• Versatility: computers are used for different jobs
like word processing, payroll calculation, internet
browsing.
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Storage Measurements
XP
 Bit Binary digit 0 or 1
 Byte = 8 bit(one character)
 Kilobyte = 1024bytes (Document)
 Megabyte = 1024KB(Floppy disk)
 Gigabyte = 1024MB(Compact disk)
 Terabyte = 1024GB(Google)
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Types of Computers
XP
• Personal computers (PCs)
– Desktop computers
– Notebook (laptop) computers
– Tablet PCs
• Handheld computers
– PDA (personal digital assistant)
– MP3 players
– Cell phones
•
•
•
•
•
Mini computers
Server
Mainframe computer
Supercomputers
Wearable
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Types of Computers
XP
• Personal Computer:
Desktop Computers: This type of computer will set up in
a permanent location. More power storage and less cost.
Laptop computers: Easy to carry everywhere.
Rechargeable batteries could be used to power them.
• Mainframe Computers: Mainframe computer is a huge
computer that can fill in a room. Used to perform
millions of transactions. It has several gigabytes of
storage.
• Super Computer: High performance computers
working in parallel as a single system. High cost.
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Types of Computers
XP
• Work Station: A desktop computer that has a more
powerful processor, additional memory and enhanced
capabilities for performing a special group of task, such
as 3D graphics or game development.
• Server: A computer that has been optimized to provide
services to other computers over a network. It has
powerful processors, lots of memory and large hard
drives.
• Mini Computer: Mini computers fall between micro
computer and mainframe computer
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Types of Computers
XP
• Wearable: The latest trends in computing is wearable
computers. Common computer applications like email,
database, multimedia are integrated into watches, cell
phones.
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Types of Computers
XP
Personal Computers
PDA
Desktop
Notebook
Tablet PC
Super Computers
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Computer Systems
XP
• Includes computer hardware and software
– Hardware refers to the physical components
of a computer
– Software refers to the intangible components
of a computer system, particularly the
programs the computer needs to perform a
specific task
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System Software
XP
• System software manages
the fundamental
operations of your
computer
– Operating system
• System resource
• Multitasking
– Utilities
– Programming Languages
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Application Software
XP
• Application software enables you to perform
specific computer tasks, such as document
production, spreadsheet calculations, and
database management
– Document production software
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Application Software
XP
• Presentation software
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Application Software
XP
– Web site creation and management software
– Spreadsheet software
– Database management software
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Application Software
•
•
•
•
XP
Photo editing software
Multimedia authoring software
Accounting software
Information management software
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XP
Architecture or configuration is the design of
the computer.
Example: what does the computer consist of?
Specification is the technical detail about each
component.
Example: How big is the monitor?
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Processing Hardware
XP
• The motherboard is the
main electronic
component of the
computer
• The microprocessor is
one of the most important
pieces of processing
hardware on the
motherboard
• Cards are removable
circuit boards
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Processing
XP
Microprocessor, also referred to
as processor or CPU (Central
Processing Unit
RAM - Random Access Memory
 Volatile
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Input and Output
XP
• The data or instructions you type into the
computer are called input
• The result of the computer processing your input
is referred to as output and also referred to as
information.
• Peripheral devices accomplish input and output
functions
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Input Devices
XP
• You use an input device, such as a keyboard or a mouse,
to input data and issue commands
– Keyboard
– Pointing device
•
•
•
•
•
Controls the pointer
Mouse
Trackball
Touch pad
Pointing stick
– Scanner
– Touch Screen
– Pen Input
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Output Devices
XP
• Output devices show
you the results of
processing data
– Monitor
• Flat panel
• LCD
• CRT
– Printer
• Laser
• Inkjet
• Dot matrix
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Data Representation
XP
• Binary digits (bits)
• A series of eight bits is called a byte
• ASCII
– American Standard Code for Information Interchange
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Memory
XP
• Random access memory (RAM)
– Volatile memory
– SDRAM
• Cache memory (RAM cache or CPU cache)
• Virtual memory
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Memory
XP
• Read-only memory (ROM)
– BIOS
– Nonvolatile memory
• Complementary metal oxide semiconductor
memory (CMOS)
• Semi permanent memory
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Method of Access
XP
 Sequential access – retrieve data in order.
 Example of media- magnetic tape
 Direct or random access – go directly to required data.
 Example of media- magnetic disk, CD-Rom, DVD
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Storage Media
XP
• A computer file is a named collection of stored
data
• An executable file contains the instructions that
tell a computer how to perform a specific task
• A data file is created by a user
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Storage Media
XP
• Magnetic media
– Hard disk
– Tape
– Floppy disk
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Hard Drive
XP
 Consists of one or more rigid metal platters
coated with a metal oxide material that
allows data to be magnetically recorded on
the surface of the platters
 The number of platters permanently
mounted on the spindle of a hard disk
varies.
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Storage Media
XP
• Optical storage device
–
–
–
–
–
CD
DVD
CD-R
CD-RW
CD-ROM
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Storage Media
XP
• Flash memory
– Flash memory cards
– USB flash storage device
– USB drive (flash drive)
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Information Processing Cycle
XP
• To understand how a computer functions you must
understand the information processing cycle.
What is the information processing cycle?
• The sequence of events in processing information, which
includes
(1) input :Input—entering data into the computer.
(2) Processing—performing operations on the data.
(3) Storage—saving data, programs, or output for future use.
(4) Output—presenting the results.
These processes work together and repeat over and over.
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Information Processing Cycle
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Data Communications
XP
• The transmission of text, numeric, voice, or video
data from one computer to another or to a
peripheral device is called data communications
– Sender and receiver
– Channel
– Protocol
– Device driver (driver)
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XP
Components of Data Communications
The four essential components of data
communications are:
• Sender
• Channel
• Receiver
• Protocols
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Data Communication
XP
A sender is the computer that originates the
message.
The message is sent over a channel, such as a
telephone
The receiver is the computer at the message’s
destination.
Protocols are the rules that establish the transfer of
data between sender and receiver.
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Networks
XP
A network connects one computer to
other computers and peripherals.
In a local area network (LAN), computers
and peripherals are close to each
other.
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Concepts
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Networks
XP
Each computer that is part of the network
must have a network interface card and
network software.
Then it becomes a workstation.
Any device connected to the network is
called a node.
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Concepts
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Telecommunications
XP
Telecommunications is communicating
over a telephone. In the
telecommunications process, the
modem converts digital signals to
analog signals at the sending site and a
second modem converts them back at
the receiving site.
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Telecommunications
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The Internet
XP
The Internet is the world’s largest
network.
E-mail and the World Wide Web are two
benefits of the Internet.
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The Internet
XP
A hyperlink is a place on a Web
page allowing you to connect to a
particular file.
http://www.course.com/newperspec
tives
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XP
The Internet
A Web browser is
the communications
software that
allows you to
navigate the
WWW.
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Concepts
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Networks
XP
• A network connects one computer to other
computers and peripheral devices, enabling you
to share data and resources with others
• Network interface card (NIC)
• LAN
• WAN
• WLAN
• PAN
• SAN
• WiMax
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Networks
XP
• LAN: A LAN is Local Area Networks joining computers in a single room,
building or site. The data is transmitted directly in binary form through the
cable that joins the computers together. (10m-10km): room, building, campus
• WAN:A WAN is Wide Area network joins computer over a wider area than a
LAN. WAN's join computers in different cities, countries or even continents.
Distance: (100-1000km)
• MAN: A Metropolitan area network (MAN) is a large computer network that
usually spans a city or a large campus. Distance:(10-100km): city (e.g., cable
TV)
• PAN :A personal area network (PAN) is a computer network used for
communication among computer and different information technological
devices close to one person. Distance: (1-10m) (e.g., wireless network
connecting computer, mouse, keyboard, and printer)
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XP
• SAN:A storage area network (SAN) is a dedicated network that
provides access to consolidated, block level data storage. A SAN
typically has its own network of storage devices that are generally
not accessible through the local area network by other devices.
Used in enterprise and small to medium sized business
environments.
• Enterprise private network:
An enterprise private network is
a network built by an enterprise to interconnect various company
sites, e.g., production sites, head offices, remote offices, shops, in
order to share computer resources.
• Wireless Network: Any form of communication that does not
require the transmitter and receiver to be in physical contact
E.g cell Phones, Satellite, Sensor
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Telecommunications
XP
• Telecommunications means communicating
over a comparatively long distance using a phone
line or some other data conduit
– Modem
• Digital and analog signals
– DSL
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The Internet
• The Internet is the largest
network in the world,
connecting millions of
people.
• “interconnected collection of
autonomous computers
connected by a single
technology”
– World Wide Web
• Web page
• Web site
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• “network of networks”
• “collection of networks
interconnected by
routers”
• “a communication
medium used by
millions”
• Email, chat, Web
“surfing”, streaming
media
– Electronic mail
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Security Threats on Your Computer
XP
• Security refers to the steps a
computer owner takes to
prevent unauthorized use of or
damage to the computer
– Malware
• Viruses
– Antivirus software
• Spyware
• Adware
• Firewall
• Phishing
• Pharming
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