SCC 311: Introduction to Distributed Systems

Flashcards reviewing key concepts from the Introduction to Distributed Systems lecture.

What is a distributed system according to Tanenbaum and van Steen?

A collection of independent computers that appears to its users as a single coherent system.

What is a distributed system according to Coulouris, Dollimore, and Kindberg?

One in which hardware or software components located at networked computers communicate and coordinate their actions only by passing messages.

List three examples of Distributed Systems

World Wide Web (WWW), Web search engines, and Blockchain Systems

Why are distributed systems important?

Because the world is distributed; joining forces increases performance and availibility.

What is a key challenge in distributed systems regarding component failure?

Tolerating certain parts of the system stopping working while the system continues to operate.

What is a fault in the context of distributed systems?

When a component of a system stops working.

How do nodes coordinate/communicate their actions in a distributed system?

Only by sending messages over a network.

What are the node failure modes?

Crash-stop (fail-stop), Crash-recovery (fail-recovery), and Byzantine (fail-arbitrarily).

What are the timing and synchrony assumptions?

Synchronous, Asynchronous, and Partially Synchronous

What do the two generals try to achieve in the Two Generals Problem?

To capture a city by having both armies attack together, despite unreliable communication.

What does the FLP impossibility theorem state?

There is no guarantee for distributed processes to reach consensus in an asynchronous environment, where it’s possible for at least one process to crash.

What is the role of Middleware in Distributed Systems?

Provide a high-level programming abstraction and hide the complexity associated with distributed systems.

Name three goals of a Middleware Platform?

Resource sharing, Transparency, and Openness