Introduction to
Computers
What is a computer?

An electronic device, operating under
the control of instructions stored in its
own memory unit, that can accept data,
manipulate the data according to
specified rules, produce information
from the processing, and store the
results for future use.
A teacher
demonstrates
the jobs of a
computer.
Inside a computer
What are the components of the
computer?
Input devices
 Central processing unit (CPU)
 Output devices
 Memory
 Storage devices

Jobs of the Computer
1.
2.
3.
4.
Accept Information
Store Information
Process Information
Give back Processed Information
Parts of the Computer
1.
2.
3.
4.
Input
Memory
Central Processing Unit
Output
Information Processing Cycle—four
general operations
Input
 Processing
 Output
 Storage

Input Devices
Keyboard
 Mouse
 Digital camera
 Scanner
 Microphone

Keyboards
Mouse Devices
Scanners
Microphones
The Central Processing Unit
The Central Processing Unit is the part
of the computer that does the
processing.
It is called the “brain” of the computer,
but does not function like a human
brain.
It has two main parts.
(c) Kathy Walsh
Central Processing Unit



Made up of the control unit and arithmetic/logic unit
The brains of the CPU is the processor. There are
different brands and speeds
– Pentium made by Intel
– Celeron made by Intel
– Athlon made by AMD
Memory
– RAM—also called Random Access Memory
Processors & Memory
Data Representation









Byte—one character of data
Kilobyte—one thousand bytes of data
Megabyte—one million bytes
Gigabyte—one billion bytes
Terabyte—one trillion bytes
Petabyte—one quadrillion bytes
Exabyte—one quintillion bytes
Zettabyte—one sextillion bytes
Yottabyte—one septillion bytes
http://www.jimloy.com/math/billion.htm
Memory

ROM
Read Only Memory
1. Built in at the factory
on a chip
2. Permanent
3. Cannot be changed
by us
4. Ex. Cursor, simple
math, how to read a
disk

RAM
 Random Access
Memory
1. Stores information
we enter, workplace
2. Temporary
3. Can be changed by
us
4. Ex. Games, typing
lessons, programs
(c) Kathy Walsh
Output Devices

Printers
– Impact printers
• Dot matrix printers
– Nonimpact printers
• Ink jet
• Laser
– Color
–B&W

Monitors
– CRT’S
– LCD’S
STORAGE DEVICES

Floppy Disks
– 3.5-inch disks store 1.44M of data
• Must be formatted
– Tracks
– sectors

Hard Disks
– Spins at 5,400 – 7,200 rpm (revolutions per minute)
– Can store anywhere between 10G – 120Petabyte+ of data

CD’s—Compact Discs
– Available in a variety of formats—CD-ROM, CD-R, CD-RW
– A typical CD holds about 650 MB of data

DVD’s
– Available as DVD-ROM, DVD-R, DVD-RW
– Can hold 4.7 GB of data

Zip Drives—high capacity floppy disk drive; has lost popularity
– Zip disks can hold from 100 MB – 250 MB of data

USB Flash Drive
– Storage capacity between 32 MB – 256 GB
STORAGE DEVICES
Software—Can be categorized into
four types
System software
 Application software
 Educational software
 Entertainment software

System Software

Controls the operations of computer equipment
 Operating System software tells the computer how
to:
– Load
– Store
– Execute
 OS is loaded into memory when the computer is
turned on
– This process is called booting
 Most OS’s use a Graphical User Interface (GUI)
– Provides visual cues such as icons
– Each icon represents an application
Application Software
Programs that tell a computer how to
produce information
 Commonly used applications

– Word processing
– Spreadsheet
– Database
– Presentation
– Financial
– Email
– Taxing
Educational Software
Software that can be used for learning
purposes
 Examples include:

– Jump Start Series
– Mavis Beacon Teaches Typing
– Reader Rabbit
– Encarta or World Book
– Math Blaster
– Rosetta Stone Spanish
Entertainment Software

Sports games
– Madden NFL
– MLB
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The Sims
World of Warcraft
Rollercoaster Tycoon
Final Fantasy
Halo
Myst
Half Life
Barbie Fashion Show
The Central Processing Unit
has two distinct parts.
Control
Arithmetic/Logic
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The job of the control is to direct
information in the computer.
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The control sends the information
where it needs to go.
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The Arithmetic/Logic has two jobs.
1.
2.
Logic=comparison
Arithmetic – add
So the Arithmetic/Logic adds and compares
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How does it do other math?
Multiplication
3X4=
4+4+4
Subtraction
7–2=
2+1+1+1+1+1
It adds and compares until it gets to 7.
Then it adds up the ones.
Division
27 / 9 =
9+9+9
It adds and compares until it gets to 27
It simply adds and compares.
What about really large numbers?
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What is the speed at which the
computer works?
A nanosecond
– one billionth of a second.
(c) Kathy Walsh
Grace Hopper – Naval Commander
Gave a good
explanation of how
fast a nanosecond
works.
http://www.cbsnews.com/8301-504803_16257389728-10391709/grace-hopper-shetaught-computers-to-talk/
(c) Kathy Walsh
Model T & Current Car
Old Computers site http://www.obsoletecomputermuseum.org/
(c) Kathy Walsh
Will computers ever work faster
than they do now?
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Can man travel the speed of sound?
Chuck Yeager was the
first man to travel
the speed of sound.
(c) Kathy Walsh
Can man travel the speed of light?
Albert Einstein’s
theory states that if
man ever travels the
speed of light – he
will travel through
time.
(c) Kathy Walsh
Computer Bug
And, if you've ever used the expression "bug" to describe a computer
malfunction or software problem, you've got Ms. Hopper to thank as
well. In 1947, something went haywire in the Mark II computer
system. Upon closer inspection, a dead moth was discovered in the
wiring and removed. From that point on, Hooper said, when anything
went wrong with the computer, everyone said "it has a bug in it.
(c) Kathy Walsh
On the test
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You will label this diagram.
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What are the two parts of the
Central Processing Unit?
1.
2.
Control
Arithmetic/Logic
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What is the job of each part?
1.
2.
The control directs information
The arithmetic/logic
1. Adds
2. Compares
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What is the speed at which the
computer works called?
a nanosecond
(c) Kathy Walsh
Chapter 6 test
1. Label the diagram
1._________
2._________
3._________
4._________
5._________
6._________
7. What is the job of the control? To direct information
8 & 9. What are the jobs of the Arithmetic/Logic? Add and compare
10. The speed at which the computer works is called a nanosecond.
(c) Kathy Walsh
-Be familiar with information on all slides.
Know the different items to be stored on
different types of storage device.
-Take a screen shot of your home computers
hard drive memory and paste it into a word
document.
Check our Computers
Storage & Memory



Take a Screen Shot of the Following 2 items and Paste them
into a Microsoft Word Document.
Click on Start, Right click on Computer, click on Properties.
(This will give you computers RAM)
Click on My Computer, hover over Hard Drive (C). (This will
give you the amount of storage on your computers Hard Drive)
(c) Kathy Walsh