Distributed Systems Course (fall 2015/2016)

Lecturer: Konrad Iwanicki
Assistants: none
Lectures: Wednesday, 2:15 PM - 3:45 PM, Room 3230
Lab classes: Wednesday, 4:15 PM - 5:45 PM, Room 3045
Final exam: Wednesday, January 27, 2:15 PM - 3:45 PM (may be shorter), Room 3230

This (sixth) edition of the course consists of two components: lectures and lab classes. The lectures cover the principles, advanced concepts, and technologies of distributed systems, including communication, replication, fault tolerance, and security. The objective of the lab, in turn, is to give every student a chance to design, implement, and evaluate his own distributed system in the area of cloud computing, as well as to broaden the students' knowledge on the state of the art in distributed systems. The course is recommended for graduate students attending the distributed systems seminar and following the DOS Master's track, as well as for other students interested in computer systems. The course may be given in English.

Passing Rules

To pass the course, a student has to score at least 60 out of a total of 100 points and pass the lab (see below). The points can be scored for:

  • lab assignments: up to 50 points
  • a written exam at the end of the semester: up to 50 points

The final grade is calculated as follows:

Points 0-51 52-59 60-67 68-75 76-83 84-91 92-...
Grade 2 (fail) 2+ (fail) 3 3+ 4 4.5 5

Lab Rules

The goals of the lab are twofold. First, the lab allows each student to build her own simple distributed system. The building process will consist of two assignments and one colloquium. Second, the lab creates an opportunity for the student to update other students with a piece of recent work in the area of distributed systems. This will have the form of an oral presentation.

To pass the lab, each student has to score a total of at least 30 points and a given number of points per each assignment. The detailed breakdown of the scores and deadlines is as follows:

What When How many points Min. required points
Colloquium October 14, 2015, 16:00 CEST 5 0
Assignment 1 October 30, 2015, 23:59 CET 10 6
Assignment 2 January 8, 2016, 23:59 CET 30 16
Oral Presentation Individually set date (schedule) 15 8

At the beginning of the course, students may decide if they want to work on the assignments individually or in pairs. No larger groups will be allowed. The decision cannot be changed during the semester (after the colloquium). The lecturer will not regard any conflicts within pairs as circumstances affecting grades. In other words, if you work in a pair, choose your partner well.

Assignment solutions have to be handed in on time by submitting e-mails with topic “[DS2015] Solution X” to the lecturer (where X can be 1 or 2). Since the lecturer receives an excessive number of e-mails, e-mails with different topics may be ignored. Moreover, each day of delay in submitting a solution results in multiplying the scores received for the solution by 0.9. Normally, the delay must not be more than 7 days, after which an assignment is considered as failed (the student receives 0 points). However, each day a student participates in both a lecture and a lab gives the student one extra day of delay (in this day, the points are not multiplied by 0.9). No future days during which the student intends to participate will be counted toward the reduction. For students working in pairs, the reduction will be counted as the average of the lectures attended by each of the participants (rounded down if necessary).

It is allowed to talk about your ideas on solving the assignments with your colleagues. It is NOT allowed to show, share, exchange code (in any form) without a prior permission from the lecturer.

A presentation is in turn prepared individually and normally given in Polish with slides in English. However, if foregin students enroll for the course, all presentations will be required to be given in English. The strict time limit of a single talk is 60 minutes, in case of one presentation per class, or 45 minutes, if there are two presentations during a single class. The presenting student will be interrupted after this period. During the talk, other students are discouraged from asking questions. After the talk, there is a questions-and-answers session, during which the presenter answers question posed by the lecturer and other students. The objective of the questions could be, for instance, to clarify some aspects of the paper or to learn the presenter's opinion on a problem related to the paper.

During her presentation of a paper, a student is obliged to display PowerPoint/PDF slides for the paper. As a reminder, they have to be in English. The student has to prepare the slides on her own. If some slides for the paper already exist on the Internet, the concents of those slides can be re-used by the student preparing her own slides only if re-using the contents does not violate any copyrights, especially when the student's presentation is made available online. Moreover, the student has to acknowledge using somebody else's slides.


  • Read your paper well in advance to understand it and to later be able to answer other students' questions.
  • Practice your talk to fit in the time limit.
  • Try to briefly go over the related work cited in the paper as this can give you some valuable input on the problem the paper is solving.
  • Try to find any follow-ups on the paper because this can be rewarding as well. Skimming through follow-up papers will help you better understand the topic.
  • Ask the presenter questions that, rather than proving the presenter doesn't know something, lead to interesting discussions. You are not awarded points for mean or stupid questions.
  • If you have read and understood the presented paper, and if you have practiced your talk, relax during your presentation: you will surely be able to answer all questions.

Exam Rules

The exam covers the lecture topics as well as the students' presentations. It consists of a series of questions. Each question has three subquestions with binary (TRUE/FALSE) answers. A students scores a point for a question only if the answers to all subquestions of the question are correct. Conversely, if an answer to any subquestion of the question is incorrect, no point is given for the entire question. Note that these scoring rules are really demanding (cf. the scores for 2012/2013).

Lecture Topics and Schedule

Since this is still a developing course, this year's lectures will be given mostly based on a book by my PhD adviser and the head of my former research group: Maarten van Steen and Andrew S. Tanenbaum, “Distributed Systems: Principles and Paradigms,” Second Edition, Prentice Hall, 2007, 702 pages, ISBN 9780132392273. Purchasing the book is not mandatory as the lecture slides will be available here. There will be a few lectures with an extra material, though.

Date Topics Slides
October 7, 2015 Introduction:
goals of distributed systems, common types of distributed systems
lecture 01
October 14, 2015 Architectures:
architectural styles, system architectures, self-management
lecture 02
October 21, 2015 Processes:
threads, virtualization, clients & servers, server clusters, code migration
lecture 03
October 28, 2015 Communication:
fundamentals, remote procedure call, message-oriented communication, stream-oriented communication, multicast communication
lecture 04-05
November 4, 2015
November 18, 2015 Naming:
basic terms and definitions, flat naming, structured naming, attribute-based naming
lecture 06
November 25, 2015 Synchronization:
clock synchronization, logical clocks, totally-ordered multicast, causally-ordered multicast mutual exclusion, global positioning of nodes, leader election
lecture 07-08
December 2, 2015
December 9, 2015 Replication and Consistency (Part I):
replica management, continuous consistency, data-centric consistency models, consistency protocols
lecture 09 (selected slides)
December 16, 2015 Fault Tolerance (Part I):
failure models, failure masking, failure detection, reliable client-server communication, atomic multicast, two-phase commit, three-phase commit, checkpointing, logging, recovery, agreement in faulty systems
lecture 10 (selected slides)
January 13, 2016 Fault Tolerance (Part II):
agreement in faulty systems (continued), Paxos
lecture 11
January 20, 2016 Replication and Consistency (Part I):
CAP theorem, PACELC, eventual consistency, conflict-free replicated data types, client-centric consistency models
lecture 12
January 27, 2016 FINAL EXAM

Lab Topics and Schedule

The schedule of the lab classes with material relevant to building the distributed system is as follows:

Date Materials
October 7, 2015 Scenario 01
October 14, 2015 Scenario 02
October 21, 2015 Scenario 03
October 28, 2015 Scenario 04
November 4, 2015 Scenario 05
November 18, 2015 Scenario 06
November 25, 2015 Scenario 07
December 2, 2015 Scenario 08
December 9, 2015 Individual work, assignment grading in spare time
December 16, 2015
January 13, 2016
January 20, 2016
January 27, 2016 Entire lab dedicated to assignment grading

Student Presentation Topics and Schedule

The schedule of the students' presentations is as follows:

Date Presenter Topic
October 7, 2015 Konrad Iwanicki Lab organization and rules. Assignment presentation.
October 14, 2015 Juliusz Straszynski Kay Ousterhout, Patrick Wendell, Matei Zaharia, Ion Stoica: “Sparrow: Distributed, Low Latency Scheduling”
October 21, 2015 Jan Wroblewski Piyus Kedia, Sorav Bansal: “Fast Dynamic Binary Translation for the Kernel”
October 28, 2015 Jakub Luczynski Eno Thereska, Hitesh Ballani, Greg O'Shea, Thomas Karagiannis, Antony Rowstron, Tom Talpey, Richard Black, Timothy Zhu: “IOFlow: A Software-Defined Storage Architecture”
November 4, 2015 Krzysztof Pachacz Matei Zaharia, Tathagata Das, Haoyuan Li, Timothy Hunter, Scott Shenker, Ion Stoica: “Discretized Streams: Fault-Tolerant Streaming Computation at Scale”
November 18, 2015 Pawel Kaminski Sameer Agarwal, Aurojit Panda, Barzan Mozafari, Samuel Madden, Ion Stoica: “BlinkDB: Queries with Bounded Errors and Bounded Response Times on Very Large Data”
November 25, 2015 Georgia Brikis Lenin Ravindranath, Jitendra Padhye, Ratul Mahajan, Hari Balakrishnan: “Timecard: Controlling User-Perceived Delays in Server-Based Mobile Applications”
December 2, 2015 Pawel Walczak Derek G. Murray, Frank McSherry, Rebecca Isaacs, Michael Isard, Paul Barham, Martin Abadi: “Naiad: A Timely Dataflow System”
December 9, 2015 Jakub Zakrzewski Qi Huang, Ken Birman, Robbert van Renesse, Wyatt Lloyd, Sanjeev Kumar, Harry C. Li: “An Analysis of Facebook Photo Caching”
Tomasz Dziopa Liang Zhang, Fangfei Zhou, Alan Mislove, Ravi Sundaram: “Maygh: Building a CDN from client web browsers”
December 16, 2015 Piotr Podolski Zhengping Qian, Yong He, Chunzhi Su, Zhuojie Wu, and Hongyu Zhu, Taizhi Zhang, Lidong Zhou, Yuan Yu, Zheng Zhang: “TimeStream: Reliable Stream Computation in the Cloud”
Lukasz Kryston Harry C. Li, Allen Clement, Edmund L. Wong, Jeff Napper, Indrajit Roy, Lorenzo Alvisi, Michael Dahlin: “BAR Gossip”
January 13, 2016 Michal Niewiadomski Tudor David, Rachid Guerraoui, Vasileios Trigonakis: “Everything You Always Wanted to Know about Synchronization but Were Afraid to Ask”
Pawel Banaszewski Stephen Tu, Wenting Zheng, Eddie Kohler, Barbara Liskov, Samuel Madden: “Speedy Transactions in Multicore In-Memory Databases”
January 20, 2016 Patryk Hes Douglas B. Terry, Vijayan Prabhakaran, Ramakrishna Kotla, Mahesh Balakrishnan, Marcos K. Aguilera, Hussam Abu-Libdeh: “Consistency-Based Service Level Agreements for Cloud Storage”
Agnieszka Paszkowska Mahesh Balakrishnan, Dahlia Malkhi, Ted Wobber, Ming Wu, Vijayan Prabhakaran, Michael Wei, John D. Davis, Sriram Rao, Tao Zou, Aviad Zuck: “Tango: Distributed Data Structures over a Shared Log”
January 27, 2016 No presentations: grading Assignment 2

Past Exams

Below, you can find the questions from past exams:

Year Exam Set Participants Points
Course Exam % Available Min Avg Med Max
2014/2015 Final (test) 17 17 100 25 5 12.76 13 20
2013/2014 Final (test) 16 16 100 25 11 14.69 13 21
2012/2013 Final (test) 34 34 100 25 3 10.33 10 22
2011/2012 Final 36 34 94.4 50 10 29.85 30.5 49
2010/2011 Part II 26 21 80.8 25 3.75 16.27 13.5 24.25
2010/2011 Late Part I 26 11 42.3 25 13.75 21.6 21.25 24.75
2010/2011 Early Part I 26 17 65.4 25 9.25 14.9 13.5 22