What you'll learn this week
By the end of Week 1 you will be able to:
- Explain cloud computing and the IaaS/PaaS/SaaS split in plain language.
- Describe AWS's global infrastructure: Regions, Availability Zones, edge locations.
- State who secures what under the shared responsibility model.
- Set up an AWS account the professional way — root locked away, MFA on, billing alarms armed.
- Run your first AWS CLI commands.
The one-sentence version
Cloud computing is renting someone else's computers by the second, over the internet, with an API. Instead of buying servers, racking them, and guessing capacity years ahead, you click (or script) and infrastructure appears — and disappears when you stop paying.
On-premises vs the service models
Think of it as who manages which layers (hardware → OS → runtime → app):
- On-premises — you manage everything, own everything, guess capacity. High control, high burden.
- IaaS (Infrastructure as a Service) — AWS gives you virtual machines, networks, disks; you manage OS and up. EC2 is IaaS. Most of this course lives here — because understanding IaaS makes everything above it make sense.
- PaaS (Platform) — you bring code; the platform runs it. Elastic Beanstalk, RDS (they run the database engine; you bring schemas and queries).
- SaaS (Software) — you just use the app. Gmail, Slack. You manage nothing but your data.
Why companies moved
- Elasticity — handle Black Friday traffic Monday, pay for a quiet Tuesday on Tuesday. Impossible with owned hardware.
- Pay-as-you-go — capital expense (buy servers) becomes operating expense (monthly bill). Startups can launch with almost nothing.
- Global reach — deploy to Sydney or São Paulo this afternoon without building a data center.
- Managed muscle — AWS runs databases, queues, and ML infrastructure with teams you could never hire.
The trade: bills that grow silently if unmanaged (this week's obsession), and a new skill set — the one you're here to build.
Try it now
Name three apps you use. For each: is it SaaS to you? What do you think it runs on underneath? (Spoiler: a very large fraction of the internet is EC2 and S3 under the hood.)