CS 345 Distributed Systems — Spring 2020

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Fabián E. Bustamante
Seely Mudd #3905
+1 847 491-2745


Byungjin Jun (Jin)
James Newman


Biraj Parikh
Adnan Turkay


Lectures: Tuesdays and Thursdays 9:00-10:20PM
Frances Searle Building 1441 | Zoom (find the room in Canvas)

Professor Office Hours:  By appointment

TA Office Hours:  By appointment

TA Sessions: TBD

Final: Take-home final, Due June 10th, 11:50PM.


Basic principles behind distributed systems (collections of independent components that appear to users as a single coherent system) and main paradigms used to organize them.



 In compliance with Section 504 of the 1973 Rehabilitation Act and the Americans with
Disabilities Act, Northwestern University is committed to providing equal access to all
programming. Students with disabilities seeking accommodations are encouraged to contact the office of Services for Students with Disabilities (SSD) at +1 847 467-5530 or ssd@northwestern.edu. SSD is located in the basement of Scott Hall. Additionally, I am available to discuss disability-related needs during office hours or by appointment.

Distributed systems are collections of networked computers that coordinate their actions through message exchanges. Most computing systems you interact with everyday are indeed distributed (e.g. email, the Web, Google, Skype, Facebook …) for a variety of reasons such as fault tolerance, performance, and the geographical nature of the requirements.

In this course, we will discuss some of the basic principles behind distributed systems as well as common approaches and techniques used to build them. We illustrate these ideas through case studies of widely used or seminal systems.


  • Remote invocation and indirect communication
  • Time and coordination
  • Overlay networks and P2P
  • Distributed storage and file systems
  • Name services
  • Global state and transactions
  • Replication and consistency
  • Consensus
  • Fault tolerance
  • Security and privacy


There are a number of communication channels set up for this class:

  • We will use the course web site to post announcements related to the course. You should check this regularly for schedule changes, clarifications and corrections to assignments, and other course-related announcements.
  • We will use Piazza for class discussion. The system is highly catered to getting you help fast and efficiently from classmates, the TA, and myself. Rather than emailing questions to the teaching staff, I encourage you to post your questions on our Piazza for DS
  • There is always email for questions that would be inappropriate to post on the newsgroup/discussion-board. When using email to contact the staff please start your subject line with “eecs345: helpful-comment” to ensure a prompt response.


The course is organized as a series of lecture and paper discussions, four projects, homework assignments and a take-home final.

  • Lectures and discussions – A set of lectures on the core of the material.
  • Readings – Textbook and paper reading in preparation for (not substitution of) the lecture.
  • Homework assignments – A set of assignments meant as reader enforcers.
  • Projects – Four programming projects to give you a better understanding of the subject matter and experience with the Go programming language.
  • A take-home final.


I use a criterion-referenced method to assign your grade; in other words, your grade will be based on how well you do relative to predetermined performance levels, instead of in comparison with the rest of the class. Thus, if a test has 100 possible points, anyone with a score of 90 or greater will get an A (90-92: A-), those with scores of 80 or greater will get a B (80-82: B-), those with scores of 70 or greater will get a C, and so on. Notice that this means that if everyone works hard and gets >93, everyone gets an A.

Total scores (between 0 and 100) will be determined, roughly, as follows:

  • Homework assignments 20%
  • Class participation 15%
  • Projects 45%
  • Take-home final 20%


Late policy:

Unless otherwise indicated, homework assignments and projects are due by midnight on their due date. If you hand in an assignment late, we will take off 10% for each day (or portion thereof) it is late. Assignments that are three or more days late receive no credit.

Cheating vs. Collaboration:

Collaboration is a really good thing and we encourage it. On the other hand, cheating is considered a very serious offense. When in doubt, remember that it’s OK to meet with colleagues, study for exams together, and discuss assignments with them. However, what you turn in must be your own (or for group projects, your group’s own) work. Copying code, solution sets, etc. from other people or any other sources is strictly prohibited.

The following is our intended calendar with topics, slides (as they become available) and reference material. Note “MSAT3 #” refers to chapters/sections of (M. van Steen and A. Tanenbaum Distributed Systems 3rd Ed., 2017); “CDKB5 #” refers to chapters/sections of (Coulouris et al. Distributed Systems: Concepts and Design, 5th Ed., 2012). Papers, except when tagged as [ref], may be part of homework assignment/finals questions. All papers are available in Canvas (“Reading” folder in the “Files” section); links in the Calendar point those files.

Week Date Topic
1 4/7 Introduction


4/9 Networking


  • MSAT3 4.1 | CDKB5 3, 4
2 4/14 Communication – RPC/RMI


  • MSAT 4.2
4/16 Distributed File Systems


3 4/21 Logical and Physical Clocks


4/23 Logical and Physical Clocks


4 4/28 Consistency and Replication


4/30 Eventual Consistency


5 5/5 Overlay Networks and Dynamo


5/7 Global State


6 5/12 Coordination – Mutual Exclusion and Elections


5/14 Consensus Impossibility


7 5/19 Consensus


5/21 Consensus


8 5/26 Transactions and Distributed Transactions


  • CDKB5 16
5/28 Transactions and Distributed Transactions


9 6/2 Name Services and Content distribution networks


6/4 Live/real-time streaming


* 6/8 Take-home final (Due June 10th, 11:59PM CST).


There are four team-based projects, some basic homework assignments, mostly meant as reading enforcers, and a take-home final.

We will post all assignments in the Canvas’ site for the course.


There will be four projects, including a MapReduce library and a replicated state machine protocol. Projects are to be done in teams of 2-3 students (1 is not allowed).

All projects will be done in Go, a language that was originally created within Google, but is now a fully open-source project. Go is garbage-collected and has built-in coroutines (called goroutines) and channels, making it highly suited to building distributed systems. Its standard library is already pretty comprehensive. For example, take a look at the net and rpc packages.




Go useful links