- [Instructor] So, how do these two numbers
give us the incredible range of things computers can do?
The first thing we need
is a way to turn these zeroes and ones
into bigger numbers.
A single zero or one is called a bit.
We need bytes.
A byte is eight bits.
It might sound a bit complicated when you first hear it
because it's such an unusual word to use,
but bits and bytes are the building blocks
of the computer world.
The system is so simple and so elegant,
it makes computers work robustly and dependably.
And it works like this.
If you line up a set of eight binary bits,
you can assign each one a number.
The numbers used start at one and double each time
until they get to 128.
So, we have one, two, four, eight,
16, 32, 64, and 128.
And let's just say that zero means off
and one means on.
So, if a binary bit is on,
we'll add that number to any other numbers that are on
to get any number from zero to 255.
Let's try this out.
All zeroes would make zero.
If the first binary bit is on, we'll have one.
If only the second binary bit is on, we'll have two.
And you can probably see already how this works.
If we turn on the first two binary bits,
we'll get the number three.
That's one plus two.
And all the other numbers are off.
If we have the first binary bit on and the seventh,
we'll have 65.
That's one plus 64.
So far, so simple.
And here's where the system becomes quite
beautifully magical.
You can create any number from zero to 255 with this system,
but with only one possible combination
of ones and zeroes each.
No two combinations of ones and zeroes
will produce the same number.
Put another way,
each number has a unique binary combination.
This feature of uniqueness makes it possible for computers
to work dependably with numbers.
Now we have numbers,
we can assign them to anything,
such as how much red there is on a pixel
or how loud a sound is.
Coincidentally, fonts are usually eight bit too,
which is why there are up 256 characters in most fonts.
Each letter has a unique number.
In terms of the amount of data being stored,
you can think of eight bits
being equivalent to one letter of text.
This means a single frame of full 1920 by 1080 HD video
in black and white,
so it has no additional color information,
takes up 2,073,600 letters worth of data.
It's enormous.