World Wide Web

Tim Berners-Lee—1990 Invented at CERN for research documents

Specialized computers

• Web servers—just serve websites
• Chat servers
• File servers
• etc.

Connected computers

Each with a unique name—the IP Address

• 127.0.0.1
• 2001:0db8:85a3:0000:0000:8a2e:0370:7334

IPs are for computers

IP addresses are confusing for humans

Domains, like github.com, are for us

DNS

(Domain Name System)

Maps Domains ⬌ IPs

Websites are lots and lots of files…

• HTML
• CSS
• JavaScript
• Images
• Video

Each downloaded separately

Performance matters

The more files the slower your website

Performance is the most important design constraint