how do computers work a gentle introduction for kids l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
How Do Computers Work? A Gentle Introduction for Kids PowerPoint Presentation
Download Presentation
How Do Computers Work? A Gentle Introduction for Kids

Loading in 2 Seconds...

play fullscreen
1 / 40

How Do Computers Work? A Gentle Introduction for Kids - PowerPoint PPT Presentation


  • 899 Views
  • Uploaded on

Final Part! How Do Computers Work? A Gentle Introduction for Kids Dr. Arturo Sanchez University of North Florida E-mail: asanchez@unf.edu Web: http://www.unf.edu/~asanchez This presentation: http://www.unf.edu/~asanchez/public/rawlings My Intention …

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'How Do Computers Work? A Gentle Introduction for Kids' - oshin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
how do computers work a gentle introduction for kids

Final Part!

How Do Computers Work? A Gentle Introductionfor Kids

Dr. Arturo Sanchez

University of North Florida

E-mail: asanchez@unf.edu

Web: http://www.unf.edu/~asanchez

This presentation: http://www.unf.edu/~asanchez/public/rawlings

my intention
My Intention …
  • To put together what we have studied so far to have an understanding of:
    • The internal organization of a computer (elements)
    • How these elements operate

How Do Computers Work? Part III Dr. A. Sanchez

acknowledgement
Acknowledgement
  • All the slides, BUT 1-3, 17-21, and 39-40, I took from the book …
  • “Java: Software Solutions – Foundations of Program Design”. By John Lewis and William Loftus. Published by Addison-Wesley, 2005. ISBN: 0-321-24583-0.

How Do Computers Work? Part III Dr. A. Sanchez

hardware and software
Hardware and Software
  • Hardware
    • the physical, tangible parts of a computer
    • keyboard, monitor, disks, wires, chips, etc.
  • Software
    • programs and data
    • a program is a series of instructions
  • A computer requires both hardware and software
  • Each is essentially useless without the other

How Do Computers Work? Part III Dr. A. Sanchez

cpu and main memory

Main

Memory

CPU and Main Memory

Chip that executes program commands

Intel Pentium 4

Sun ultraSPARC III

Central

Processing

Unit

Primary storage area for programs and data that are in active use

Synonymous with RAM

How Do Computers Work? Part III Dr. A. Sanchez

secondary memory devices

Hard Disk

Main

Memory

Floppy Disk

Secondary Memory Devices

Secondary memory

devices provide

long-term storage

Information is moved

between main memory

and secondary memory

as needed

Central

Processing

Unit

Hard disks

Floppy disks

ZIP disks

Writable CDs

Writable DVDs

Tapes

How Do Computers Work? Part III Dr. A. Sanchez

input output devices

Monitor

Keyboard

Hard Disk

Main

Memory

Floppy Disk

Input / Output Devices

I/O devices facilitate

user interaction

Central

Processing

Unit

Monitor screen

Keyboard

Mouse

Joystick

Bar code scanner

Touch screen

How Do Computers Work? Part III Dr. A. Sanchez

software categories
Software Categories
  • Operating System
    • controls all machine activities
    • provides the user interface to the computer
    • manages resources such as the CPU and memory
    • Windows XP, Unix, Linux, Mac OS
  • Application program
    • generic term for any other kind of software
    • word processors, missile control systems, games
  • Most operating systems and application programs have a graphical user interface (GUI)

How Do Computers Work? Part III Dr. A. Sanchez

analog vs digital
Analog vs. Digital
  • There are two basic ways to store and manage data:
  • Analog
    • continuous, in direct proportion to the data represented
    • music on a record album - a needle rides on ridges in the grooves that are directly proportional to the voltages sent to the speaker

How Do Computers Work? Part III Dr. A. Sanchez

analog vs digital10
Analog vs. Digital
  • Digital
    • the information is broken down into pieces, and each piece is represented separately
    • music on a compact disc - the disc stores numbers representing specific voltage levels sampled at specific times

How Do Computers Work? Part III Dr. A. Sanchez

digital information
Digital Information
  • Computers store all information digitally:
    • numbers
    • text
    • graphics and images
    • video
    • audio
    • program instructions
  • In some way, all information is digitized - broken down into pieces and represented as numbers

How Do Computers Work? Part III Dr. A. Sanchez

representing text digitally

72 105 44 32 72 101 97 116 104 101 114 46

Representing Text Digitally
  • For example, every character is stored as a number, including spaces, digits, and punctuation
  • Corresponding upper and lower case letters are separate characters

H i , H e a t h e r .

How Do Computers Work? Part III Dr. A. Sanchez

binary numbers
Binary Numbers
  • Once information is digitized, it is represented and stored in memory using the binary number system
  • A single binary digit (0 or 1) is called a bit
  • Devices that store and move information are cheaper and more reliable if they have to represent only two states

How Do Computers Work? Part III Dr. A. Sanchez

binary numbers14
Binary Numbers
  • A single bit can represent two possible states, like a light bulb that is either on (1) or off (0)
  • Combinations of bits are used to store values

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations

1 bit

2 bits

3 bits

4 bits

0

1

00

01

10

11

000

001

010

011

100

101

110

111

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

1111

Bit Combinations

Each additional bit doubles the number of possible combinations

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations16

1 bit ?

2 bits ?

3 bits ?

4 bits ?

5 bits ?

How many

items can be

represented by

Bit Combinations
  • Each combination can represent a particular item
  • There are 2N combinations of N bits
  • Therefore, N bits are needed to represent 2N unique items

21 = 2 items

22 = 4 items

23 = 8 items

24 = 16 items

25 = 32 items

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations17
Bit Combinations
  • Suppose we have three bits … see how different numbers are represented with them

1

0

1

5

22 = 4

0

1

5

+

+

=

1

1

1

7

22 = 4

21 = 2

1

7

+

+

=

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations18
Bit Combinations
  • Since you were very small, people have told you that you can count up to 10 with your two hands, right?
  • Well … you can do better than this …
  • With one hand you can count up to 31 …
  • With two hands you can count up to 1023 …
  • How

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations19

21 = 2

22 = 4

23 = 8

24 = 16

2

1

3

20 = 1

4

0

Bit Combinations

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations20
Bit Combinations

NOT Showing

SHOWING!

What number is this??

1

How Do Computers Work? Part III Dr. A. Sanchez

bit combinations21
Bit Combinations

NOT Showing

SHOWING!

What number is this??

NOT Showing

2

How Do Computers Work? Part III Dr. A. Sanchez

a computer specification
A Computer Specification
  • Consider the following specification for a personal computer:
    • 2.8 GHz Pentium 4 Processor
    • 512 MB RAM
    • 80 GB Hard Disk
    • 48x CD-RW / DVD-ROM Combo Drive
    • 17” Video Display with 1280 x 1024 resolution
    • 56 Kb/s Modem
  • What does it all mean?

How Do Computers Work? Part III Dr. A. Sanchez

memory

9278

9279

9280

9281

9282

9283

9284

9285

9286

Main memory is divided into many memory locations (or cells)

Each memory cell has a numeric address, which uniquely identifies it

Memory

Remember this?

How Do Computers Work? Part III Dr. A. Sanchez

storing information

Each memory cell stores a set number of bits (usually 8 bits, or one byte)

Large values are

stored in consecutive

memory locations

Storing Information

9278

9279

9280

9281

9282

9283

9284

9285

9286

10011010

How Do Computers Work? Part III Dr. A. Sanchez

storage capacity
Storage Capacity
  • Every memory device has a storage capacity, indicating the number of bytes it can hold
  • Capacities are expressed in various units:

Unit Symbol Number of Bytes

KB 210 = 1024

kilobyte

megabyte

gigabyte

terabyte

MB 220 (over 1 million)

GB 230 (over 1 billion)

TB 240 (over 1 trillion)

How Do Computers Work? Part III Dr. A. Sanchez

memory26
Memory

Meaning

Pronunciation

  • Main memory is volatile - stored information is lost if the electric power is removed
  • Secondary memory devices are nonvolatile
  • Main memory and disks are direct access devices - information can be reached directly
  • The terms direct access and random access often are used interchangeably

How Do Computers Work? Part III Dr. A. Sanchez

memory27
Memory
  • A magnetic tape is a sequential access device since its data is arranged in a linear order - you must get by the intervening data in order to access other information

How Do Computers Work? Part III Dr. A. Sanchez

ram vs rom
RAM vs. ROM
  • RAM - Random Access Memory (direct access)
  • ROM - Read-Only Memory
  • The terms RAM and main memory are basically interchangeable
  • ROM could be a set of memory chips, or a separate device, such as a CD ROM

How Do Computers Work? Part III Dr. A. Sanchez

ram vs rom29
RAM vs. ROM
  • Both RAM and ROM are random (direct) access devices!
  • RAM probably should be called Read-Write Memory

How Do Computers Work? Part III Dr. A. Sanchez

compact discs
Compact Discs
  • A CD-ROM is portable read-only memory
  • A microscopic pit on a CD represents a binary 1 and a smooth area represents a binary 0
  • A low-intensity laser reflects strongly from a smooth area and weakly from a pit

How Do Computers Work? Part III Dr. A. Sanchez

compact discs31
Compact Discs
  • A CD-Recordable (CD-R) drive can be used to write information to a CD once
  • A CD-Rewritable (CD-RW) can be erased and reused
  • The speed of a CD drive indicates how fast (max) it can read and write information to a CD

How Do Computers Work? Part III Dr. A. Sanchez

slide32
DVDs
  • A DVD is the same size as a CD, but can store much more information
  • The format of a DVD stores more bits per square inch

Meaning and Pronunciation

DVD = Digital Versatile Disk

Read More HERE

How Do Computers Work? Part III Dr. A. Sanchez

slide33
DVDs
  • A CD can store 650 MB, while a standard DVD can store 4.7 GB
    • A double sided DVD can store 9.4 GB
    • Other advanced techniques can bring the capacity up to 17.0 GB
  • Like CDs, there are DVD-R and DVD-RW discs

How Do Computers Work? Part III Dr. A. Sanchez

the c entral p rocessing u nit cpu

Retrieve an instruction from main memory

fetch

execute

decode

Carry out the

instruction

Determine what the

instruction is

The Central Processing Unit (CPU)
  • A CPU is on a chip called a microprocessor
  • It continuously follows the fetch-decode-execute cycle:

How Do Computers Work? Part III Dr. A. Sanchez

the central processing unit
The Central Processing Unit
  • The CPU contains:

Performs calculations and makes decisions

Arithmetic / Logic Unit

Coordinates processing steps

Control Unit

Small storage areas

Registers

How Do Computers Work? Part III Dr. A. Sanchez

the central processing unit36
The Central Processing Unit
  • The speed of a CPU is controlled by the system clock
  • The system clock generates an electronic pulse at regular intervals
  • The pulses coordinate the activities of the CPU
  • The speed is usually measured in gigahertz (GHz)

How Do Computers Work? Part III Dr. A. Sanchez

monitor
Monitor
  • The size of a monitor (17") is measured diagonally, like a television screen
  • Most monitors these days have multimedia capabilities: text, graphics, video, etc.
  • A monitor has a certain maximum resolution , indicating the number of picture elements, called pixels, that it can display (such as 1280 by 1024)
  • High resolution (more pixels) produces sharper pictures

How Do Computers Work? Part III Dr. A. Sanchez

modem
Modem
  • Data transfer devices allow information to be sent and received between computers
  • Many computers include a modulator-demodulator or modem, which allows information to be moved across a telephone line
  • A data transfer device has a maximum data transfer rate
  • A modem, for instance, may have a data transfer rate of 56,000 bits per second (bps)

How Do Computers Work? Part III Dr. A. Sanchez

questions
Questions?

How Do Computers Work? Part III Dr. A. Sanchez