So far, we've been talking about AWS like it's just one thing, but it's not.

AWS is actually a whole constellation of services

which can be used together or separately.

Each service in AWS has it's own name and they all do different things and

cost different amounts.

In this video, we'll talk about the two biggest most popular services in AWS.

S3 and EC2.

S3 stands for simple storage service, and

it's probably the simplest service that AWS offers.

As the name implies, S3 is used for storage.

You put data into it, and then take it back out again.

That's all.

Nothing particularly complicated.

S3 will hold whatever data you want for as long as you want.

As we discussed in the last video, the cost for

using S3 is based on space multiplied by time.

The more data you store, and the longer you store it, the more it will cost.

But don't worry, S3 is remarkably cheap.

You could store 100 GB in S3 for a year.

And it would cost less than $50.

Then there's EC2.

EC2 stands for elastic compute cloud, and it's used for processing and computation.

With EC2, you basically rent a computer from Amazon and

you can run whatever programs you want on that computer.

This computer is called an instance, and

it works a bit differently from your computer at home.

For starters, an EC2 instance doesn't come with a hard drive.

In order to read and write data on an EC2 instance, you need to connect it to one of

the data storage services that AWS provides, such as S3.

The cost for using EC2 is also based on space multiplied by time.

For EC2, the space part of the equation is based on factors like processor speed,

write speed, available RAM, and so on.

The time part of the equation is based on how long the instance is running.

You can also run multiple instances simultaneously.

You can run one instance for eight hours or two identical instances for

four hours and it costs the same amount.

It's important to point out that the cost is based on time not activity.

An EC2 instance that is working as hard as it can

costs the same amount as an EC2 instance that is sitting idle doing nothing.

Amazon keeps on charging for the instance as long as it's running.

So if you're not using an instance, you can shut it down to save money.

EC2 can be very cheap, or very expensive, depending on how you use it.

Fortunately if you're new to AWS, Amazon will let you try it out for free.

For the first year after you sign up for an AWS account, Amazon will let you store

a little bit of data on S3 and run a small EC2 instance for no charge.

Pretty cool, right?

Amazon is hoping that you'll start using AWS, even for free, so that they can start

charging you money after your free trial expires at the end of one year.

Check out the teacher's notes for more information.

There's a lot more to AWS than just S3 and EC2,

but those two services are the most important ones to know.

In the next stage of this course, we'll dive into S3 and

learn how to use it to store and retrieve files.

We won't be spending any more time on EC2 in this course, but

don't worry, there's another course for that coming up in the future.