CAS CS451/651 Distributed Systems
Spring 2013

Department of Computer
College of Arts and Science

"A distributed system is a collection of independent computers that appears to its users as a single coherent system." [Tanenbaum and Steen 2006]. Every major internet service is a distributed system. Examples include Google, Facebook, Youtube, banking websites and for that matter the World Wide Web itself. Other fundamental services such as Global Positioning Systems (GPS), Domain Name Services (DNS) and email are also distributed systems. For students to be effective, today and in the future, as decision makers, technical advisors, innovators and implementors they should be familiar with the principles and paradigms that underlying this important class of systems.

This page
the course piazza site


The server for the course is up and running. Please do all your course related work on curzon. curzon can only be accessed from within the bu network so you will first need to login to one of the external cs servers such as csa3 or csa2 and the ssh to curzon.
Added a piazza site for this course. Please enroll yourself. In general all announcements and news will be on piazza
Welcome! Here's to a fun term hacking!


Prof. Jonathan Appavoo
Math & Computer Science Building Office: 284
111 Cummington Street, Boston, MA
Phone: (617) 358-1062
Email: jappavoo (at)
Office Hours: Tuesday, Wednesday 5:00pm - 6:00pm
To reach me at times other than my office hours, please send me email.

The purpose of the office hours of the Instructor is to answer specific questions or clarify specific issues. Office hours are not to be used to fill you in on a class you skipped or to explain entire topics.

Time And Place

Tuesday, Thursday 9:30am to 11:00am
CAS 212

Course Description


CS451/651 (Distributed Systems) is a fast-paced, broad and practical introduction to the fundamentals of distributed systems. The course first examines foudational topics such as: System Models, Networking, Interprocess Communications, Remote Invocation, Indirect Communications, and Operating Systems Support. After covering the foundations a selection of topics will be covered from: Distributed algorithms, Shared data, Middleware, System services. A major goal of the course is to provide practical exposure to distributed systems through a term long programming project in which small groups of students construct a distributed game using 'C'. The project requires significant programming effort.

Formal Description

Programming-centric introduction to how networks of computers are structured to operate as coherent single system. Introducing principles of architecture, processes, communications, naming, synchronization, consistency and replication, fault tolerance and security, and paradigms such as web-based, object-based, file systems, and coordination-based.


The prerequisites for this course are CS 210 Computer Systems and CS112. Students without the prerequisites will not be allowed to enroll in the course.

Grade Breakdown

Your final grade will be determined approximately as follows:

Take Home Midterm 15%
Take Home Final 25%
Assignments 25%
Project 35%

Weekly Class Structure and Evaluation

The class meets twice a week. In general the weekly sessions will be divided into a lecture session and a lab session. The lab session will be more interactive in nature and focus on programming topics and guiding the development of the term projects. As part of the lab sessions the instructor will evalute project progress and comprehension of the lecture material.

Project and Workload

Be forewarned the workload in this course will be heavy. To master the conceptual material covered in the lecture and prepare you for completion of the project there will be weekly reading and programming required outside of class time.

The course is organized around a term-long programming project that constitutes 35% of the grade. The project will utilize a library of foundational components that will be in part developed by the students during the semester. Additional components will be provide by the instructor. The goal of the project is two fold, firstly to allow the principles and paradigms covered in class to be utilized and explored practically and secondly to get exposure to the process of system construction, including design, software development, documentation, testing and debugging.

The project this year will be a distributed capture the flag style game.

The projects will be evaluated along 3 main dimensions, design, project management, and functionality. Design will be judged based on accompanying documentation that the students will prepare describing their system with respect to organization, software structure and choices made. Project management will be evaluated based on a project log that the students will submit. The logs will document weekly project meetings in which students are expected to identify status with respect to implementation progress, problems encountered, and what is to be done in the following week. Finally project functionality will be evaluating using a test suite designed to validate protocol adherence and various test-cases such as scalability and unexpected disconnection. Each group will do a final presentation of their projects to the instructor during the schedule final exam time.


Please come and discuss the additional requirements with the instructor.

Class Schedule

Special Dates

You should be sure to be familar with the Official Semester Dates

Some of the critical Semester Dates are below:

Weekly Schedule

The following is the tentative schedule that will be adjusted as necessary





1 Jan 16 Lecture: Introduction and Class Overview
DSPP: Chapter 1
2 Jan 22, 24 Lecture: Architectures
Lab: Crash course on 'C' and UNIX Network Programming.
DSPP: Chapter 2
3 Jan 29, 31 *Lab: TBA
Lecture: Processes
DSPP: Chapter 3
4 Feb 5, 7 Lecture: Communications
Lab: TBA
DSPP: Chapter 4
5 Feb 12, 14 Lecture: Communication
Lab: TBA
DSPP: Chapter 4
6 Feb 19, 21 Lecture: Communication
Lab: TBA
DSPP: Chapter 4
7 Feb 26, Feb 28 Lecture: Naming
Lab: TBA
DSPP: Chapter 5
8 Mar 5, 7 Lecture: Naming
Lab: TBA
DSPP: Chapter 5
9 Mar 19, 21 Lecture: Syncronization
Lab: TBA
DSPP: Chapter 6
10 Mar 26, 28 Lecture: Syncronization
Lab: TBA
DSPP: Chapter 6
11 Apr 2, 4 Lecture: Consistency and Replication
Lab: TBA
DSPP: Chapter 7
12 Apr 9, 11 Lecture: Consistency and Replication
Lab: TBA
DSPP: Chapter 7
13 Apr 16 Lecture: Overview Spanner
Lab: TBA
14 Apr 23, 25 Lecture: Paper Review Spanner
Lab: TBA
15 Apr 30, May 2 Lab: Game Eval Lab: Game Eval


The following is the tentative dates for the exams.




MidTerm Out March 5, Due March 23 @ 4:30am Solutions
Final Out May 2, Due on Day of Exam: TBA NONE

Assignement Material

If there is any information for a give lab it will be posted here.




Assignment 1 Due: Jan 31 writeup, files
Assignment 2 Due: Feb 22 writeup, files
Assignment 3 TBA writeup, files
Assignment 4 TBA TBA


[DS:CS Required Text] Andrew S. Tanenbaum and Maarten Van Steen, Distrib uted Systems Principles and Paradigms,

[UNP] Another useful text, which covers network programming in C, that we will rely on is Richard Stevens, Bill Fenner and Andrew M. Rudoff, "UNIX Network Programming - The Sockets Networking API.", 3ed. Addison-Wesley Professional, ISBN-10: 0131411551 ISBN-13: 978-0131411555.

Boths books are available from the BU bookstore.

[optional] Brian W. Kernighan and Rob Pike, "The UNIX Programming Environment", Prentice Hall, 1984. (Another Classic Text).

Online References


GNU/Unix Tools

The GNU project provides online manuals for all of the GNU tools, including:


Academic Honesty

Assignments must be completed individually. Discussion of issues in computer systems is encouraged, but representing the work of another person as your own is expressly forbidden. This includes "borrowing", "stealing", copying programs/solutions or parts of them from others. We may use an automated plagiarism checker. Cheating will not be tolerated under any circumstances. Handing in your own work a day or two late will affect your grade far less than turning in a copy of someone else's work on time!

See the CAS Academic Conduct Code, in particular regarding plagiarism and cheating on exams. Copies of the CAS Academic Conduct Code are also available in room CAS 105. A student suspected to violate this code will be reported to the Academic Conduct Committee, and if found culpable, the student will receive a grade of "F" for the course.

Last modified: Fri Feb 1 11:25:01 EST 2013