Distributed Computing
ETH Zurich

Distributed Systems (HS 2023)

Course Catalogue

Note: This course is part of the course "Computer Systems" (252-0217-00L), but can also be taken as a standalone course: "Distributed Systems" 227-0555-00L. For the full course held together with Professor Roscoe visit the corresponding webpage and the corresponding internal moodle.

This course introduces the fundamentals of distributed systems. We study different protocols and algorithms that allow for fault-tolerant operation, and discuss practical systems that implement these techniques. The objective of the course is for students to understand the theoretical principles and practical considerations of distributed systems. This includes the main models of fault-tolerant distributed systems (crash failures, byzantine failures, and selfishness), and the most important algorithms, protocols and impossibility results. By the end of the course, students should be able to reason about various concepts such as consistency, durability, availability, fault tolerance, and replication.

Topics: client-server, serialization, two-phase protocols, three-phase protocols, paxos, two generals problem, crash failures, impossibility of consensus, byzantine failures, agreement, termination, validity, byzantine agreement, king algorithm, asynchronous byzantine agreement, authentication, signatures, reliable and atomic broadcast, eventual consistency, blockchain, cryptocurrencies such as bitcoin and ethereum, proof-of-work, proof-of-*, smart contracts, quorum systems, fault-tolerant protocols such as piChain or pbft, distributed storage, distributed hash tables, physical and logical clocks, causality, selfishness, game theoretic models, mechanism design.

Course pre-requisites: None.

Course language: English.

Lecture by Roger Wattenhofer, Monday and Friday 10.15-12.00 @ CAB G 61.

Videos Videos of the lectures can be found on the ETH Video Portal.

Exercises Wednesday 10.15-12.00 @ HG E 21 lead by Loic Holbein (holbeinl@student.ethz.ch). Exercises start one week after lecture start. We will not provide recordings of the exercise sessions.

Q&A Students can self-enroll using the password received by email in order to access the moodle Q&A board (shared with Computer Systems).

Organization by Yann Vonlanthen.

Last year's script: You can find last year’s script here.

Word of advice from the professor: Instead of attending this course, you can also just read The Saddest Moment by James Mickens, the guy who continuously tried to convince me that having vodka shots at a local Denny's at 3am is how I should spend my nights. Just reading Mickens will not give you any credits though.


03.09.2023Course website updated.
31.10.2023The course starts on November 6. The first exercise session will take place on November 15.
15.11.2023Option to access a Q&A forum was added (see above).
16.11.2023Prof. Wattenhofer has been involved in an accident, during his recovery Teaching Assistants will assume teaching duties.
17.11.2023 Chapter 18 and chapter 19 will be taught by Andrei Constantinescu.
20.11.2023Chapter 19 notes were updated (small fixes and new remark).
23.11.2023Chapter 18 (Broadcast & Shared Coins): Section 18.4 is not exam material.
24.11.2023Chapter 20 and chapter 21 will be taught by Diana Ghinea.
24.11.2023Chapter 20 notes were updated (small fixes).
30.11.2023Chapter 22 will be taught by Robin Fritsch and Till Aczél.
03.12.2023Chapter 23 and chapter 25 will be taught by Yann Vonlanthen.
04.12.2023There will be no lecture on Friday, 08.12.23. Instead, the lecture is flipped, meaning you can watch the set of videos at your own pace.
06.12.2023Chapter 16 exercise slides, assignment and solution were updated to match the Ben-Or pseudocode from the lecture notes.
19.12.2023Definition 24.16 was updated in the script.
05.01.2023Added an optional bonus video for chapter 24.

Lecture Material

Lecture material and exercise sheets will be uploaded here as the lecture progresses. Note that chapter numbers are aligned with the course "Computer Systems".

Title Lecture Notes Exercises Additional Material
Chapter 14
Date: 06-November-2023
PDF --- ---
Chapter 15
Fault Tolerance & Paxos
Date: 06-November-2023
PDF --- Recording from 2020
Chapter 16
Date: 10-November-2023
PDF Exercises
Recording from 2020
Exercise Slides
Chapter 17
Byzantine Agreement
Date: 14-November-2023
PDF --- Recording from 2020
Chapter 18
Broadcast & Shared Coins
Date: 17-November-2023
PDF Exercises
Recording from 2020
Exercise Slides
Chapter 19
Quorum Systems
Date: 21-November-2023
PDF --- Recording from 2020
Chapter 20
Approximate Agreement
Date: 24-November-2023
PDF Exercises
New Recording
Exercise Slides
Chapter 21
Consistency & Logical Time
Date: 27-November-2023
PDF --- Recording from 2020
Chapter 22
Time, Clocks & GPS
Date: 01-December-2023
PDF Exercises
Recording from 2020
Exercise Slides
Chapter 23
Distributed Storage
Date: 04-December-2023
PDF --- Recording from 2020
Chapter 24
Game Theory
Date: 08-December-2023
Flipped Classrom Playlist
Recording from 2020
Exercise Slides
Bonus Video
Chapter 25
Eventual Consistency and Bitcoin
Date: 11-December-2023
PDF --- Recording from 2020
Chapter 26
Internet Computer
Date: 15-December-2023
PDF --- Recording
Internet Computer Slides
Chapter 27
Advanced Blockchains
Date: 18-December-2023
PDF Exercises
Lecture Slides
Exercise Slides
No lecture
Date: 22-December-2023
--- --- ---

Exam Preparation

To get an idea for the style of questions in the exam, you may consult exams from previous years: HS09, HS10, HS11, HS12, HS13, HS14, HS15, HS16, HS18, HS19, HS20, HS21. HS22. Beware that the topics covered have shifted around a little over the years, so some older exams have questions about topics that are not in the lecture anymore. Some of the older exams are in German, but this year’s exam is in English.