Remember when I said that a computer is a device that
stores and processes data by performing calculations?
Whether you're creating
an artificial intelligence that can be
humans at chess or
something more simple like running a video game,
the more computing power you have access to,
the more you can accomplish.
By the end of this lesson,
you'll understand what a computer calculates and how.
Let's look at this simple math problem.
Zero plus one equals what?
It only takes a moment to come up with the answer one,
but imagine that you needed to do
100 calculations that were this simple.
You could do it, and if you are
careful you might not make any mistakes.
What if you needed to do 1,000 of these calculations?
How about a million?
How about a billion? This is
exactly what a computer does.
A computer simply compares ones and zeros,
but millions or billions of times per second.
\[inaudible\]. The communication that a computer uses is
referred to as binary system,
also known as base-2 numeral system.
This means that it only talks in ones and zeros.
You may be thinking,
my computer only talks in ones and zeros.
How do I communicate with it? Think of it like this.
We use the letters of the alphabet to
form words and we give those words meaning.
We use them to create sentences,
paragraphs and whole stories.
The same thing applies to binary,
except instead of A, B, C,
and so on, we only have zero
and one to create words that we give meaning to.
In computing terms, we group
binary into eight numbers or bits.
Technically, a bit is a binary digit.
Historically, we use
eight bits because in the early days of computing,
hardware utilized the base-2 numeral system
to move bits around.
Two to the eighth numbers offered us
a large enough range of
values to do the computing we needed.
Back then, any number of bits was used,
but eventually the grouping of eight bits
became the industry standard that we use today.
You should know that a group of eight bits
is referred to as a byte.
A byte of zeros and ones could look like 10011011.
Each byte can store one character,
and we can have 256 possible values
thanks that a base-2 system, two to the eighth.
In computer talk, this byte
can mean something like the letter
c. This is how a computer language is born.
Let's make a quick table to translate something
a computer might see
into something we'd be able to recognize.
What does the following translate to?
Did you get hello? Pretty cool.
By using binary, we can have
unlimited communication with our computer.
Everything you see on your computer right now,
whether it's a video,
an image, texts or anything else,
is nothing more than a one or a zero.
It is important that you understand how binary works.
It is the basis for everything
else we'll do in this course.
Make sure you understand the concept before moving on.
By the end of this video,
you'll learn how we can represent the words, numbers,
emojis, and more we see on our screens from
only these 256 possible values.
It's all thanks to character encoding.
Character encoding is used to assign
our binary values to
characters so that we as humans can read them.
We definitely wouldn't want to see
all the texts in our emails in
webpages rendered in complex sequences of zeros and ones.
This is where character encodings come in handy.
You can think of character encoding as a dictionary.
It's a way for your computers to look up
which human character should be
represented by a given binary value.
The oldest character encoding standard used is ASCII.
It represents the English alphabet,
digits, and punctuation marks.
The first character in the ASCII to
binary table, a lowercase a,
maps to 01100001 in binary.
This is done for all the characters
you can find in the English alphabet,
as well as numbers and some special symbols.
The great thing with ASCII was that we only needed to use
127 values out of our possible 256.
It lasted for a very long time,
but eventually, it wasn't enough.
Other character encoding standards were
created to represent different languages,
different amounts of characters, and more.
Eventually, they would require
more than 256 values we are allowed to have.
Then came UTF-8,
the most prevalent encoding standard used today.
Along with having the same ASCII table,
it also lets us use a variable number of bytes.
What do I mean by that? Think of any emoji.
It's not possible to make emojis with
a single byte since we can
only store one character in a byte.
Instead, UTF-8 allows us to
store a character in more than one byte,
which means endless emoji fun.
UTF-8 is built off the Unicode Standard.
We won't go into much detail,
but the Unicode Standard helps us
represent character encoding in a consistent manner.
Now that we've been able to represent letters, numbers,
punctuation marks, and even emojis,
how do we represent color?
Well, there are all kinds of color models.
For now, let's stick to a basic one
that's used in a lot of computers,
RGB or red, green, and blue model.
Just like the actual colors,
if you mix a combination of any of these,
you'll be able to get the full range of colors.
In computer learn,
we use three characters for the RGB model.
Each character represents a shade of the color,
and that then changes the color
of the pixel you see on your screen.
With just eight combinations of zeros and ones,
we're able to represent everything
that you see on your computer from
a simple letter a to the very video
that you're watching right now. Very cool.