🧩 Function-Based Servers (What They Do)

1. Web Server

Purpose: Delivers websites to users’ browsers over HTTP/HTTPS.

How it works: It receives requests for webpages and returns HTML/CSS/JS files.

Examples:

• Apache HTTP Server – popular open-source server used for websites like Wikipedia.
• Nginx – high-performance, often used for load balancing (used by Netflix, Airbnb).
• Microsoft IIS – used in Windows environments.

2. Database Server

Purpose: Stores and manages structured data.

How it works: Applications send queries (like SQL) to retrieve, insert, or update data.

Examples:

• MySQL – used in WordPress websites and many startups.
• PostgreSQL – known for advanced features, used by Instagram.
• MongoDB – a NoSQL database used in Node.js applications.
• Oracle DB – used in enterprise ERP systems.

3. File Server

Purpose: Provides centralized access to files and folders over a network.