Before any of the details, the big idea. This chapter gives "the cloud" a plain, concrete meaning, explains why it exists at all, and introduces the handful of words — renting versus buying, IaaS, PaaS, SaaS, public and private — that frame everything else in the course.
5 topics
"The cloud" is one of the most-used and least-explained words in technology. People keep their photos there, companies run on it, the news talks about it — and almost no one stops to say what it actually is. This chapter starts exactly there.
Five short topics lay the foundation. First, the plain meaning of the cloud — no mystery, no marketing. Then why it exists: the real problems it solves. Then the money idea at its heart — renting instead of buying. And finally two pairs of words you'll hear constantly: the IaaS / PaaS / SaaS ladder, and the public, private, and hybrid models. Get these, and the rest of the course has somewhere to land.
What "the cloud" really is, from the top down
Your apps and data
the website, the photos, the software you use
Running on rented computers
you pay for a slice, you don't own the machine
In a provider's data centers
real buildings full of machines, somewhere on Earth