The Cloud Explained

You've heard "the cloud" about a million times by now. Companies store stuff "in the cloud." Apps run "on the cloud." So what does that actually mean?

Here's the simple truth... the cloud is just someone else's computer.

That's it. Really.

What "The Cloud" Actually Means#

When a company says your photos are "stored in the cloud," they mean your photos are saved on THEIR computers, sitting somewhere in the world and hooked up to the internet.

Here's a simple way to picture the before and after.

• Before the cloud. Companies had to buy their own computers (servers), set them up in a room, keep them running and fix them every time they broke.
• With the cloud. Companies rent computer power from big providers like Amazon, Google or Microsoft, and there's no hardware to babysit.

Why Does This Matter?#

Say you want to start an online business. Back in the day, you'd have to do all of this.

1. Buy expensive server computers
2. Find somewhere to keep them (with good cooling and security)
3. Set up all the software yourself
4. Stay up all night when something breaks
5. Buy even more computers if your business grows

With cloud computing, the list looks a lot friendlier.

1. Sign up for a service
2. Start using it right away
3. Pay only for what you use
4. Let the provider handle the technical stuff
5. Scale up or down with a few clicks

One thing I'll add from experience. Renting computer power is one thing, but renting your WHOLE business setup is another. I once had a rented all-in-one stack break a client flow I'd spent weeks tuning, and I only found out on a Monday when dozens of forms were dead. Renting the computers is fine (everybody does it), just know what you actually control.

Cloud Services You Already Use#

You use the cloud every single day without even thinking about it.

Google Drive / Dropbox / iCloud#

When you save a document to Google Drive, it's not on your computer. It's on Google's computers. That's why you can do stuff like this.

• Open your files from any device
• Share files with people easily
• Stop worrying about losing everything if your laptop dies

Netflix#

Netflix doesn't mail you a DVD anymore. When you hit play, here's roughly what happens.

1. Your device sends a request to Netflix's servers
2. Netflix figures out which copy of the video is closest to you
3. The video streams to you and you watch it instantly

Fun twist... Netflix actually runs its app on Amazon's cloud (called AWS), even though the two compete in streaming! The video itself mostly comes from Netflix's own servers parked inside internet providers' networks, so it has a shorter trip to your couch.

Gmail / Outlook#

Your emails aren't really stored on your phone or computer. They live on Google's or Microsoft's servers. That's why you can do this.

• Check email from your phone, laptop or any browser
• Search through YEARS of old emails instantly
• Stop worrying about losing your inbox when your phone dies

Spotify#

Those millions of songs aren't sitting on your phone. When you tap play, Spotify streams the music from their cloud to your device.

The Big Cloud Providers#

Three companies run most of the cloud.

Provider	Name	Used By
Amazon	AWS (Amazon Web Services)	Netflix, Airbnb, NASA
Microsoft	Azure	Adobe, BMW
Google	Google Cloud	Spotify, PayPal

These companies have massive buildings called data centers packed with thousands of computers. The data centers are spread all over the world, so your data is usually somewhere nearby (which makes things faster).

Types of Cloud Services#

The cloud comes in a few different flavors.

Storage#

Save files, photos and data. Think Google Drive, iCloud and Dropbox.

Computing Power#

Rent computer processing power to run programs. This is where websites and apps actually run.

Databases#

Store and organize big piles of information (like every user of an app).

Special Services#

Stuff like AI, machine learning, email sending and plenty more, all available to rent so you don't have to build it yourself.

Benefits of the Cloud#

Step 1. No Hardware Headaches#

You don't have to buy, maintain or repair physical servers. The cloud provider handles all of that.

Step 2. Pay for What You Use#

Instead of buying a big server that sits around doing nothing most of the day, you pay only for the computer power you actually use. It's like paying your electric bill instead of buying a power plant.

Step 3. Scale Instantly#

Busy day? The cloud can automatically give you more power. Slow day? It scales back down. Try doing THAT with a closet full of physical hardware.

Step 4. Access from Anywhere#

Since everything lives on the internet, you and your users can get to it from any device, anywhere in the world.

Step 5. Redundancy (Which Is Not the Same as a Backup)#

A lot of cloud storage services keep several copies of your data on different machines, sometimes in different data centers. If one server or one building has a bad day, your stuff usually survives somewhere else.

Here's the catch though. Those copies follow whatever you do. Delete a file or let a bug overwrite your database, and every copy changes right along with it. The big providers spell this out in what they call a "shared responsibility" model. They keep the hardware running, and protecting your data (backups included) is still your job. Most of them sell backup tools, you just have to actually turn them on.

TL;DR#

• The cloud is just computers owned by someone else, hooked up to the internet
• Big companies (Amazon, Microsoft, Google) run most of the cloud
• Cloud computing means you don't have to own or maintain hardware
• You already use the cloud every day (email, streaming, file storage)
• The cloud makes it easier and cheaper to build and run software

What's Next?#

You've got all the building blocks now, meaning how the internet works, frontend versus backend and what the cloud really is. Next lesson we'll snap those pieces together and see how they connect when you actually use a website or app...