Binary Numbers

Remember we count using the decimal system or Base 10.That means there are 10 symbols: 0,1,2,3,4,5,6,7,8 and 9

Computers use the Binary or Base 2 system. They can only use 0 and 1 to represent numbers

Recap

How do they do it?

16 8 4 2 1

0 1 1 0 1

Using the binary system we represent numbers in the following way.What number are we representing with this Binary code?

Using the cards on your desk can each group show me the binary code for the following decimal numbers.

Your term to be a computer!

19

27

6

12

We can also go the other way. write down the decimal numbers that are represented by the following Binary codes.

Pop Quiz!

00110

11010

11100

10101

10011

How can we use binary to represent things other than numbers?

How can we represent an image using Binary?

How does a computer store an image when it can only use Binary numbers?

What good is Binary?

A VERY Simple example

Run length compression

Example

How could we extend this idea so that we were also able to represent different colours?

We can use another number to represent the colour of the run i.e.

1 = red, 2 = Blue, 3 = Yellowso3,2 would be a run of 3 pixels each coloured blue

What about colour?

Example

List 5 reasons in your book

Why is compression important?

-Files are smaller

-Files run more smoothly

-Saves time transferring or uploading files

-Less chance of errors or glitches

-Does not require a high spec, expensive machine

Copy out the Data Standards table from p148, provide the definition for each acronym and

it’s use.

Data Standards

Type of data

Standards Definition Used for

Images

JPEG

GIF Graphic Interchange File

Animations for the web

TIFF

BMP

Sound

WAV

MP3

AU