Theory of Distributed Computing

Fall 2016

Usually, the best way to contact me is by email. Please use your cse account when sending me email, and start your subject line with "[6117]". Send messages in plain text, without attachments.

- (Nov 10) The make-up class on Monday, Nov 14 will be in room 211 of Calumet College from 1:00 to 2:30 p.m.
- (Oct 3) When stating the bit complexity in your answer to Assignment 2, your answer should be stated in terms of n, m and k (not just n and m).
- (Sep 22) As mentioned in class, I will be away September 26-30. So we will reschedule the Sep 27 and Sep 29 classes to another time.
- (Sep 12) The location of the class has been updated above.

- shared-memory and message-passing models of distributed systems,
- mutual exclusion,
- agreement problems (consensus, leader-election, Byzantine agreement, approximate agreement),
- broadcast and multicast algorithms,
- impossibility results and lower bounds,
- the consensus hierarchy,
- implementing shared data structures,
- randomization in distributed computing,
- self-stabilization, and
- a theoretical model for mobile computing.

Marking scheme

Homework exercises | 60% |

Wikipedia assignment | 20% |

Presentation | 20% |

The presentation will be a 25-minute talk at the end of the term summarizing the results of a research paper on the theory of distributed computing that you find in the literature. We will have some checkpoints along the way before the presentations. (More information on this to come.) Good places to look for a paper include PODC or DISC conference proceedings or the journal Distributed Computing. This survey paper has a bibliography containing lots of papers that would be suitable to choose. If you have a topic in mind, I might be able to help you find a good paper if you come talk to me.

Important Dates

First class | Thursday, September 8 |

Reading day (no class) | Thursday, October 27 |

Deadline to drop course | Friday, November 11 |

Last class | Thursday, December 1 |

The references below are intended for students who want to read more about the topics discussed in class. Sometimes the readings might be helpful for the assignments. Sometimes they will extend the ideas covered in lectures.

- September 8: Introduction describing what the course is about. Two Generals problem. (See these notes from an earlier year.)
- September 13: Dijkstra's mutual exclusion algorithm. [Dij65], some notes
- September 15: Modelling distributed systems. [LL90]
- September 20: Flooding to achieve broadcasting and building a spanning tree [AW04, Chapter 2.2-2.3 or Lyn96, Chapter 15.3 or San06, Chapter 1.5, 2.1]
- September 22: Distributed MST algorithm [GHS83 or Lyn96, Chapter 15.5]
- October 4: Leader Election [AW04, chapter 3]
- October 11: Byzantine Agreement [AW04, chapter 5.2], [Lynch96, chapter 6].
- October 18: Synchronous consensus with halting failures [AW04, chapter 5.1]
- October 25: Linearizability [HW90]
- November 1: Implementing registers from message passing [ABD95], snapshots [AW04, chapter 10.2-10.3, AADGMS93]
- November 8: Counters
- November 10: Wait-free consensus [FLP85, AW04 Section 5.3.1, Her91]
- November 15: Universality of Consensus [Her91]
- November 17: Non-blocking data structures: stack [Tre86, HS08 chapter 11]
- November 21: Non-blocking data structures: BST [EFRV10]
- November 22: Renaming [AW04 Section 16.3, MA94]
- December 14: Presentations (1-4pm):
- Yifan Li: A tight space bound for consensus
- Dekun Jack Wu: Recoverable mutual exclusion
- Ezra Schwartz: The computability of relaxed data structures: queues and stacks as examples
- Khadijah Alroogi: Vertex colouring
- Bao Xin Chen: Fair synchronization

- [AE14] Hagit Attiya and Faith Ellen.
*Impossibility Results for Distributed Computing*. Morgan & Claypool, 2014. - [AW04] Hagit Attiya and Jennifer Welch.
*Distributed Computing: Fundamentals, Simulations and Advanced Topics, 2nd edition*. Wiley, 2004. - [GR06] Rachid Guerraoui and Luís Rodrigues.
*Introduction to Reliable Distributed Programming.*Springer, 2006. - [HS08] Maurice Herlihy and Nir Shavit.
*The Art of Multiprocessor Programming*. Morgan Kaufmann, 2008 - [Lyn96] Nancy A. Lynch.
*Distributed Algorithms*. Morgan Kaufmann, 1996. - [San06] Nicola Santoro.
*Design and Analysis of Distributed Algorithms*. Wiley, 2006. - [Tau06] Gadi Taubenfeld.
*Synchronization Algorithms and Concurrent Programming*. Pearson Education, 2006.

- [AADGMS93] Yehuda Afek, Hagit Attiya, Danny Dolev, Eli Gafni, Michael Merritt and Nir Shavit. Atomic snapshots of shared memory.
*J. of the ACM*, 40(4), pages 873-890, September 1993. - [Ang80] D. Angluin. Local and global properties in networks of processors. In
*Proc. 12th ACM Symposium on Theory of Computing*, pages 82-93, 1980. - [AADFP06] Dana Angluin, James Aspnes, Zoë Diamadi, Michael J. Fischer and René Peralta. Computation in networks of passively mobile finite-state sensors.
*Distributed Computing*, 18(4), pages 235-253, 2006. - [ABD95] Hagit Attiya, Amotz Bar-Noy and Danny Dolev, Sharing memory robustly in message-passing systems.
*J. of the ACM*, 42, p124-142, 1995. - [ABDPR90] Hagit Attiya, Amotz Bar-Noy, Danny Dolev, David Peleg and Rüdiger Reischuk. Renaming in an asynchronous environment.
*J. of the ACM*, 37(3), pages 524-548, July 1990. - [AGPV90] Baruch Awerbuch, Oded Goldreich, David Peleg and Ronen Vainish. A trade-off between information and communication in broadcast protocols.
*J. of the ACM*, 37(2), pages 238-256, April 1990. - [BG93] P. Berman and J. Garay. Cloture votes: n/4-resilient distributed consensus in t+1 rounds.
*Mathematical Systems Theory*26(1), pages 3-19, 1993. - [BW01] Saâd Biaz and Jennifer L. Welch. Closed form bounds for clock synchronization under simple uncertainty assumptions.
*Information Processing Letters*, 80, pages 151-157, 2001. - [Dij65] E. W. Dijkstra. Solution of a problem in concurrent programming control .
*Communications of the ACM*, 8(9), page 569, September, 1965. A very early paper on mutual exclusion. - [Dij74] Edsger W. Dijkstra. Self-stabilizing systems in spite of distributed control.
*Communications of the ACM*, 17(4), pages 643-644, November 1974. - [DM90] Cynthia Dwork and Yoram Moses. Knowledge and common knowledge in a Byzantine environment: Crash failures.
*Information and Computation*, 88(2), pages 156-186, October 1990. - [EFR08] Faith Ellen, Panagiota Fatourou and Eric Ruppert. The space complexity of unbounded timestamps.
*Distributed Computing*, 21(2), pages 103-115, 2008. - [EFRV10] Faith Ellen, Panagiota Fatourou, Eric Ruppert and Franck van Breugel. Non-blocking Binary Search Trees. In
*Proc. 29th ACM Symposium on Principles of Distributed Computing*, pages 131-140, 2010. - [FR03] Faith Fich and Eric Ruppert. Hundreds of impossibility results for distributed computing. In
*Distributed Computing*, 16(2-3), pages 121-163, 2003. - [FLP85] Michael J. Fischer, Nancy A. Lynch and Michael S. Paterson. Impossibility of distributed consensus with one faulty process.
*Journal of the ACM*, 32(2), pages 374-382, April 1985. - [GHS83] R. G. Gallager, P. A. Humblet and P. M. Spira. A distributed algorithm for minimum-weight spanning trees.
*ACM Transactions on Programming Languages and System Sciences*, 5(1), pages 66-77, 1983. - [HMM85] Joseph Y. Halpern, Nimrod Megiddo and Ashfaq A. Munshi. Optimal precision in the presence of uncertainty.
*Journal of Complexity*, 1, pages 170-196, 1985. - [Her91] Maurice Herlihy. Wait-free synchronization.
*ACM Transactions on Programming Languages and Systems*, 13(1), pages 124-149, January 1991. - [HR95] Maurice Herlihy and Sergio Rajsbaum. Algebraic topology and distributed computing: A primer. In
*Computer Science Today: Recent Trends and Developments*, pages 203-217. Springer, 1995. - [HS99] Maurice Herlihy and Nir Shavit. The topological structure of asynchronous computability.
*Journal of the ACM*, 46(6), pages 858-923, November 1999. - [HW90] Maurice P. Herlihy and Jeannette M. Wing. Linearizability: A correctness condition for concurrent objects.
*ACM Transactions on Programming Languages and Systems*, 12(3), pages 463-492, July 1990. - [Lam74] Leslie Lamport. A new solution of Dijkstra's concurrent programming problem.
*Communications of the ACM*, 18(8), pages 453-455, August 1974. - [LL90] Leslie Lamport and Nancy Lynch. Distributed Computing: Models and methods. In
*Handbook of Theoretical Computer Science*, Volume B, Chapter 18, Elsevier, 1990. (On reserve in Steacie Library.) A good, brief introduction to the area. It describes aspects of distributed models and surveys some important early results. - [LM85] Leslie Lamport and P. M. Melliar-Smith. Synchronizing clocks in the presence of faults.
*J. of the ACM*, 32(1), pages 52-78, 1985. - [MA94] Mark Moir and James H. Anderson. Fast, Long-Lived Renaming. In
*Proc. of the 8th International Workshop on Distributed Algorithms*, pages 141-155, 1994. (There have been several better versions of adaptive renaming algorithms published afterwards, but I just want to cover the most basic version of the splitter algorithm. See Mark Moir's page for some of the improvements.) - [Tau04] Gadi Taubenfeld. The black-white bakery algorithm and related bounded-space, adaptive, local-spinning and FIFO algorithms. In
*Distributed Computing, 18th International Conference*, pages 56-70, 2004. - [Tre86] R.K. Treiber. Systems programming: Coping with parallelism. Tech report RJ5118, IBM Almaden Research Center, 1986.

- The ACM Symposium on Principles of Distributed Computing (PODC) and the International Symposium on Distributed Computing. These are the main conferences for the theory of distributed computing.

**Important note on collaboration on homework assignments**: It is okay to discuss the *general* approach to solving a problem with your classmates. However, you should not take any written notes away from such a discussion, and you should write up your solution on your own. Also, to protect yourself against charges of plagiarism, you should write on the front page of your assignment the names of any classmates that you discussed the problem with, and any outside sources that you used.

- Exercise 1
- Exercise 2
- Exercise 3
- Exercise 4
- Wikipedia assignment
- Presentation suggestions
- Exercise 5
- Exercise 6
- Exercise 7

*This page was last updated on November 26, 2016
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