Big Idea: The cloud works because workloads are split across many machines (distributed computing) and made flexible with virtualization.

• Distributed Computing:
  • Instead of one big computer, many smaller computers (servers) work together.
  • Like a swarm of ants: one can’t lift much, but together they carry heavy loads.
  • Enables scaling up/down → Netflix streaming thousands of movies at once.
• Virtualization:
  • Using software to run multiple “virtual” computers on one physical server.
  • Example: A single server in AWS data center can host dozens of “virtual machines” for different customers.
  • Made cloud cost-effective: you don’t rent the whole server, just the resources you need.
• Hypervisors: The software that makes virtualization work (VMware, Hyper-V, KVM).

Key Takeaway: Virtualization + distributed computing = foundation of modern cloud.