Distributed Systems Overview

Definition and Basic Terminologies

• A distributed system is a group of computers working together to appear as a single computer to the end-user.
• A distributed system is a collection of independent components located on different machines that share messages with each other to achieve common goals.

Why Build a Distributed System?

• A single interface to the end-user
• Maximizes resources and information while preventing failures
• Provides reliability, as if one system fails, it won't affect the availability of the service
• Allows for scaling and growth of systems

Centralized System vs. Distributed System

• Centralized system: State stored on a single computer, simpler, easier to understand, and can be faster for a single user
• Distributed system: State divided over multiple computers, more robust, more scalable, and more complex

Characteristics of Distributed Systems

• Network that connects all components
• Hardware or software that enables communication with an IP address
• Messages passed between machines contain forms of data that the systems want to share (databases, objects, files)
• Reliable communication is crucial, including sending, receiving, acknowledging, and retrying on failure

Architecture Types of Distributed Systems

Client-Server Architecture

• A server as a shared resource (printer, database, or web server)
• Multiple clients use the shared resource

Three-Tier Architecture

• Clients no longer need to be intelligent, relying on a middle tier for processing and decision-making
• Most first web applications fall under this category
• The middle tier could be called an agent that receives requests from clients and forwards it on to the servers

Multi-Tier (n-Tier) Architecture

• Enterprise web services created n-tier or multi-tier systems architectures
• Interacts with data tiers and presentation tiers
• Example: google.com

Peer-to-Peer Architecture

• No centralized or special machine that does the heavy lifting and intelligent work
• Decision-making and responsibilities are split among the machines involved
• Each machine can take on client or server roles
• Example: Blockchain

This quiz covers the basics of distributed systems, including definitions, types, architectures, and examples. It also touches on cloud computing service and deployment models.