l CIS 505: Software Systems (Fall 2019)
CIS 505: Software Systems (Fall 2019)

Image of a router
This course provides an introduction to fundamental concepts of distributed systems, and the design principles for building large-scale computational systems.

We will study some of the key building blocks – such as synchronization primitives, group communication protocols, and replication techniques – that form the foundation of modern distributed systems, such as cloud-computing platforms or the Internet. We will also look at some real-world examples of distributed systems, such as GFS, MapReduce, Spark, and Dynamo, and we will gain some hands-on experience with building and running distributed systems.

CIS 505 is one of the core courses in the MSE and EMBS programs, and its final exam qualifies as one of the WPE-I exams in the PhD program.


Linh Thi Xuan Phan
Office hours: Wednesdays 1:30-2:30pm (Levine 576)

When and where:
Mondays/Wednesdays 12:00-1:30pm, Skirkanich Auditorium

Teaching assistants:
Robert Gifford
Office hours: Mondays 10:00-11:00am
Location: Levine 5th floor bump space

Saket Karve
Office hours: Mondays 3:00-4:00pm
Location: GRW 5th floor bump space

Garvit Khandelwal
Office hours: Tuesdays 2:00-3:00pm
Location: Levine 5th floor bump space

Varad Deshpande
Office hours: Tuesdays 3:00-4:00pm
Location: Levine 6th floor bump space

Akhilesh Gupta
Office hours: Wednesdays 4:00-5:00pm
Location: Levine 5th floor bump space

Waley Zhang
Office hours: Wednesdays 5:00-6:00pm
Location: Levine 6th floor bump space

Michael Henehan
Office hours: Thursdays 3:00-4:00pm
Location: Levine 5th floor bump space

Max Demoulin
Office hours: Thursdays 4:00-5:00pm
Location: Levine 6th floor bump space

Neeraj Gandhi
Office hours: Fridays 9:00-10:00am
Location: Levine 6th floor bump space

Chris Fischer
Office hours: Fridays 11:00-12:00pm
Location: Levine 5th floor bump space

Course policies

Course textbook:
Distributed Systems: Principles and Paradigms, 3rd edition (by M. van Steen and A. Tanenbaum; ISBN 978-1543057386). You can get a digital version of this book for free; hardcopies are available, e.g., from Amazon. Additional material will be drawn from selected research publications.

Either undergraduate networking or operating systems is required. You should also be comfortable with programming in C/C++.

The course will involve three substantial programming assignments, a group project, a midterm, and a final examination.

Your letter grade will be based on the programming assignments (30%), the group project (25%), the midterm exam (15%), the final exam (25%), and your participation (5%).


We will be using Piazza for all course-related discussions.

Homework assignments and project are available for download; you can submit your solution online. If necessary, you can request an extension for your homeworks.

PennCloud Award

Winners of the 2018 PennCloud Award
Garvit Gupta, Shiva Suri, Anant Maheshwari
and Sahana Vijaya Prasad
Spring 2018 PennCloud Project
Example services of the winning project.

The Spring 2018 PennCloud Award went to Garvit Gupta, Anant Maheshwari, Sahana Vijaya Prasad, and Shiva Suri for the overall best final project. The team presented a solid design of a fault-tolerant cloud platform with strong consistency, qourum-based replication, and efficient checkpointing and recovery. The platform provides a diverse set of services with multiple useful features, such as a webmail service that supports multiple users, mail folders, sorting and labeling; a storage service that supports uploading and downloading of files in any format; and a user-friendly admin console. Besides these core functionalities, the platform also offers users a novel and beautifully-designed tic-tac-toe game that is built on top of group communication.

You can read more about winners and their projects in the CIS505 Hall of Fame.

Schedule (Tentative)

Date Topic Details Reading Remarks
Aug 28 Introduction [.pdf] Course overview
Chapter 1  
Sep 2 Labor Day - No class HW0
Sep 4 Processes and threads [.pdf] Basic concepts
The UNIX model
Implementation in the kernel
Chapter 3.1 (Sections 1+2) HW0 due (on 9/6); HW1
Sep 9 System calls [.pdf] System calls
The file API
Kernel entry/exit
Sep 11+16 Concurrency control [.pdf] Synchronization primitives
Race conditions, critical sections
Deadlock and starvation
Sep 18 Synchronization [.pdf] Semaphores
Classical synchronization problems
Monitors and condition variables
Sep 23 Communication [.pdf] Sockets
Socket programming
Handling multiple connections
Chapters 4.1+4.3 + 3.1 (Section 3) HW1 due (on 09/20); HW2
Sep 25 Remote Procedure Calls [.pdf] Programming model
Stub code; marshalling; binding
Handling failures
Chapters 4.2+8.3  
Sep 30 Naming [.pdf] Kinds of names; name spaces
The Domain Name System
Chapter 5 HW2MS1 due (on 10/01)
Oct 2+7 Clock synchronization [.pdf] Logical clocks
Distributed mutual exclusion
Chapters 6.1–6.3  
Oct 7 Last day to drop  
Oct 9 Distributed coordination [.pdf]
Midterm review
Distributed mutual exclusion
Leader election
Bully algorithm; token ring
Chapter 6.4  
Oct 10–13 Fall break  
Oct 14 Class is canceled - Linh is at ESWeek HW2MS2+3 due
Oct 16 Midterm The midterm will cover topics from the first lecture  
Oct 21 Group communication [.pdf] Reliable multicast
IP multicast
FIFO, causal and total ordering
Chapter 8.4  
Oct 23 Algorithms for FIFO, causal and total ordering HW3
Oct 28 Replication [.pdf] Primary/backup protocols
Quorum protocols
Sequential and causal consistency
Client-centric models
Chapter 7 Project
Oct 30 Bigtable and Project [.pdf] Bigtable case study
Project overview
Nov 4 Fault tolerance [.pdf] 2PC and 3PC
Logging and recovery
Chandy-Lamport algorithm
Chapters 8.5+8.6; [Chandy-Lamport]  
Nov 4 Last day to withdraw
Nov 6 State-machine replication [.pdf] Failure models
The Consensus problem
Chapters 8.1+8.2; [Paxos] HW3 due (on 11/8)
Nov 11 Non-crash Fault Tolerance [.pdf] The Byzantine Generals problem
Impossibility results
[BFT] Project proposal due
Nov 13
Nov 18 Distributed file systems [.pdf] NFS
Disconnected operation
Chapter 2.4.2; [Coda]  
Nov 20 Google File System [.pdf] Google cluster architecture
Reading and writing in GFS
Consistency and fault tolerance
[Cluster] [GFS]  
Nov 25 MapReduce [.pdf] MapReduce programming model
System architecture
Nov 27 Thanksgiving break - no class (Friday schedule)  
Dec 2 Spark [.pdf] Differences to MapReduce
Case study: PageRank
Dec 4+9 DHTs and Dynamo
Exam review
Distributed hash tables
The CAP dilemma
Amazon Dynamo
Dec 10–11 Reading days
Dec 12 Final Exam (12-2pm) The final exam will cover all topics studied in the entire semester
Dec 13–Dec 19 Project demos and reports

Web site contact: Linh Thi Xuan Phan