Transcript Chapter 1

Chapter One: Introduction To
Computer
Chapter One: Introduction To Computer
•
•
•
General IT Concepts
Computer Hardware
• Types of Software
• Information Networks
The Use of Computer in our life
General IT Concepts
• What is Computer?
– A computer is a programmable machine designed
to sequentially and automatically carry out a
sequence of arithmetic and logical operations.
General IT Concepts
• Hardware
• Software
• Network
• Information Technology
Types of Computers
• Mainframe Computers
– Mainframe Computers are used for highly critical
applications such as bulk data processing. Most of
the mainframe computers have the capacities to
host multiple operating systems and operate as a
number of virtual machines and can thus
substitute for several small servers.
Types of Computers
• Desktops
– A desktop is intended to be used on a single
location
Types of Computers
• Laptops
– laptop computers are optimized for mobile use.
Laptops run on a single battery or an external
adapter that charges the computer batteries. They
are enabled with an inbuilt keyboard, touch pad
acting as a mouse and a liquid crystal display.
Types of Computers
• Personal Digital Assistants (PDAs)
– It is a handheld computer and popularly known as
a palmtop. It has a touch screen and a memory
card for storage of data. PDAs can also be
effectively used as portable audio players, web
browsers and smart phones
Hardware
• Central Processing Unit and its Functions
– Performing calculation:- when there are numbers to add or other
calculations to perform, it happens in the CPU.
– Controlling logic: - often your computer makes choices: which color to
display, what calculation to perform, and so on. The logic of these
choices is embodied in the CPU.
– Immediate access memory: - The CPU contains a small amount of fast
memory to store immediate results that it will need immediately. This
memory is called Cache.
– Coordinating other function: - The CPU sends instructions to other
components, such as sound card, video card and hard drive telling
them what to do.
Memory
• RAM
–
When you run an application, the computer code that makes up that
application and the results of your work are temporarily stored in RAM
.
– RAM is comparatively inexpensive and can be reused many times by
your computer; each part of the memory can be written to or read
from repeatedly.
– RAM is also volatile. That is, anything stored only in RAM is lost when
turned off the computer.
Memory
• ROM
– ROM is smaller area of memory that holds critical
applications that run the computer itself. Information
stored in ROM is there permanently, even when the
computer is turned off. Most computers use ROM to hold
the basic programs that make the computer and its display
come alive and become ready to hold other information.
Memory
• What is a bit?
– A single bit is equal to either a numerical 1 or 0 at
any given time. Each bit of memory is like tiny
switch that the computer can turn on or off. On
equals 1 and off equals 0. This system is called
binary system
Memory
• A byte is 8 bits.
• A kilobyte (KB) is 1024 bytes.
• A megabyte (MB) is 1024 KB or roughly one
million byte.
• A gigabyte (GB) is 1024 MB or roughly one
billion byte.
• A terabyte (TB) is 1024 GB or roughly one
trillion byte.
Input Devices
1. A mouse is an input devices designed to be held with
one hand and slide around on disk. The computer translates
this movement into the movement of the cursor on your
screen. The mouse has also one or more buttons that you
can press to send instructions to the computer.
Input Devices
2. A keyboard is an input device that includes the standard
typewriter keys and other keys such as function keys, arrow keys, and
numeric keypad. The keyboard is the device most often used to input
text to a computer program.
Input Devices
3. A trackball resembles an upside-down mouse. The trackball stays
in one spot on your desk, with a ball facing upward. Moving the ball
moves the cursor onscreen. Like a mouse, a trackball has one or more
buttons that you can press.
Input Devices
4. A scanner is an input device that can convert a printed sheet of
paper (or other flat object) into a file that the computer can store.
Some scanners are standalone device, whereas others are built into
printer or other multipurpose devices
Input Devices
5. A touchpad is a small rectangular area, usually built into a laptop
computer, where you can drag your finger to move the cursor on the
screen
Input Devices
6. A light pen looks a bit like a penlight with cord coming out of the
end. You can indicate a spot on your computer monitor by pointing at it
with the light pen and clicking a button.
Input Devices
• A digital camera
– allows you to take pictures without film by storing them in memory
inside the camera. Then by using special cable, you can load them into
the computer
Output Devices
• A Monitor
– is a video display device sometimes informally called computer’s
screen. It is the main place where you will receive information from
the computer.
Output Devices
• A printer
– is an output device suited to produce printed output on paper. There
are a wide variety of printers; they differ in their speed, size of the
paper printed, cost and the process that they use for printing.
Output Devices
• A plotter
– is device that moves one or more pens over a piece of paper to create
a drawing. Plotters are typically used for output such as architectural
drawing and mechanical design.
Storage Devices
• A diskette
– is small removable storage device, sometimes
called a “ Floppy disk”
Storage Devices
• A Zip disk
– is a proprietary device about the size of a diskette
but with hard plastic shell and much higher
storage capacity.
Storage Devices
• A CD-ROM is a plastic disk, similar to music CD.
• Internal and external hard drives are permanently
sealed magnetic storage devices that are capable of
storing large amount of data. Internal hard drives are
inside the housing of the computers. External hard
drives are the ones that can connect to the computer
outside the computer housing.
Software
• What is a Software?
• Types of Software:
• Operating System Software
– Operating system software is the software that provides the
basic functions of the computer.
• Application Software
– all software other than the operating system, that are written
for specific reason are called application software such as
accounting software, game software,
Examples of Operating System
• Microsoft Windows is the most common graphical operating system used
today. Microsoft has released a number of versions of windows over the
years. Windows versions commonly used in current business environment
include windows XP, Vista, and window 7.
• Linux is a popular open source operating system; open source means that
you can download it from the internet for free.
• DOS is text only operating system. It is created by Microsoft and it
commonly refers to Microsoft MS-DOS.
• MAC OS is the most recent operating system developed by Apple company
for its Macintosh computers.
Examples of Application Software
• Accounting Software is used to track credits, debits, and other
accounting data. Microsoft ERP Great Plains is example of
such software.
• Web Browsing Software is used to view contents of web sites.
Microsoft Internet Explorer is an example of such software.
• Desktop Publishing Software is used to create newsletters,
magazines, and other documents suitable for printing.
Microsoft publisher is an example of such software.
• Presentation Software is used to create slide show and other
speaker aids. Microsoft Power Point Presentation is an
example of such software.
Examples of Application Software
• Word Processing Software is used to write letters,
reports and other documents. Microsoft Word is an
example of such software.
• Spread Sheet is used to carryout financial,
engineering, and other calculation. Microsoft Excel is
and example of such software.
• Database Software is used to store information such
as sales, customer, address, and inventory for future
use. Microsoft Access and Oracle database are
examples of such software.
• Email Software is used to send, receive, and store
electronic mails. Microsoft Outlook is an example of
such software.
Network
•
•
What is a Network?
LAN vs. WAN
–
There are two major types of computer network: Local
Area Network (LAN) and Wide Area Network (WAN). The
difference between LAN and WAN is simple. When the
computers at single location are interconnected to form
a network, this is a LAN. When computers at different
locations are interconnected to form huge network, this
is a WAN. A WAN might connect two or more LAN.
Benefits of Network
• Hardware Sharing: a network lets you share expensive
hardware such as fast printer and plotter; so that not every
user must have his own printer and plotter.
• Better Communication: a network enables group
communication application such as email and instant
messaging.
• Application Sharing: a network let you run application on
server, instead of installing them on each individual computer.
• Shared Knowledge: a network lets you share important files
and information between users so that each user can have
updated information.
The Use of Computers in our Life
• Email
• E-Commerce
• E-Government