CS240: Advanced Topics in Operating Systems

Winter 2003 -- Dawson Engler


Solutions to the final midterm are available here. The graded midterms have been placed in the file cabinet on the fourth floor of Gates where the handouts are kept. The mean score for this midterm was 25.23.

Class Abstract

Students will study advanced operating system topics and be exposed to recent developments in operating systems research. This course involves readings and lectures on classic and new papers. Topics: virtual memory management, synchronization and communication, file systems, protection and security, operating system structure and extension techniques, fault tolerance, and history and experience of systems programming.

Class Times

Section 1: MWF 1:15-2:05 in Gates B12
Section 2: MWF 2:15-3:05 in Gates B12
(You may choose which section you wish to attend.)

Course Staff


Dawson Engler
Office: 314 Gates
Telephone: (650) 723-0762
E-mail: engler@cs.stanford.edu
Office hours: By appointment

Teaching Assistant

Shivnath Babu
Office: 438 Gates
Telephone: (650) 725-4312
E-mail: shivnath@CS.Stanford.EDU
Office hours: Tue/Thu 1:00-3:00 Gates 438

Course Secretary

Pamela Elliot
Office: 303 Gates
Phone: (650) 725-3726
E-mail: pamela@csl.stanford.edu

Mailing List

There is a mailing list for contacting the staff: cs240-win0203-staff@lists.stanford.edu. Questions and comments should be sent there. Please prefix the subject line with "CS240" for a prompt response. Announcements from the staff will be sent via the cs240-win0203-students@lists.stanford.edu mailing list to which any registered student will automatically be added to. If you are not registered for the class then subscribe to the cs240-win0203-guests mailing list by emailing majordomo@lists.stanford.edu with the body of the message saying "subscribe cs240-win0203-guests."


The prerequisite for this class is CS 140 (previously CS 240A) or the equivalent. It is necessary to have this background before taking the class, as we'll read a lot papers quickly without much time for catching up on the basics. The course assumes an understanding of topics in operating systems such as synchronization, virtual memory management, scheduling, and file systems.

The other requirement is that students be able to send and receive email, access the class newsgroup, access the class web page, and download and print postscript from the class web page. There will be very few handouts in the course, since most of the notes and other materials will be available only on the class web page.

Course Organization and Workload

The course consists of lectures, readings, and three exams. As the quarter progresses there may be ways to get extra credit. The two most important things to know about the class: (1) the main goal is to have interesting in-class discussions and (2) we recommend you read each paper at least twice, preferably more than a day in advance so that it sinks in.

Most of the work in this course consists of reading journal and conference papers. We will cover one paper for each class meeting. Unlike past quarters this class will be primarily discussion based, rather than organized as lectures. Active discussion will (hopefully) give you a non-trivial understanding of the material. The only way this approach can work is if you read the papers carefully. To encourage this, 40% of your class grade will come from class participation: this includes talking in class, as well as how you do on pop quizzes and (possibly) pop presentations. Class time will not be used to rehash the material in the papers. Instead, it will be used to highlight the important points and discuss some of the more interesting features. There will be as much as 10-15 hours of reading per week. Do not take this course unless you are willing and able to do a lot of reading.


There is no textbook for this course. The course is based on a collection of journal and conference papers that describe the history and state of the art in operating systems. Papers will be discussed in class in approximately the order that they appear on the reading list. You must read the papers before class. At a minimum we recommend two close readings. We will provide most papers online; those that are only available in hardcopy will be provided about a week before they are needed.

Grading Policy

The class is graded on a rough curve with an average grade being a B+. 40% of your grade will come from class participation, the other 60% will be based on the best out of two midterm exam scores and the final exam score. There will be no papers to write as was previously stated on the website. Because of the experimental nature of the course, the grading will not be very strict.


Two midterm exams and a final exam will be given in class. They will be open book . The exam with the lowest score will be dropped. The midterm exams are not cumulative, but the final exam is cumulative. There will be no makeup exams. If you miss a midterm exam, consider that exam to be the one of the two midterms that is dropped for calculating your grade. Missing both of them or the final exam is unacceptable. A sample exam will be available along with sample solutions. Review sessions will be held before each exam. Note that the last exam is held during dead week!

Special offer: you can write your own exam questions! Submit a question with your solution in advance of the exam, and if we like it, it will appear on the exam.

Sample Exams

The sample exams are from past midterms and they contain questions from papers that will not be covered this quarter. You can ignore these questions.
  1. Sample midterm 1     We did not cover the XFS paper.
  2. Sample midterm 2     Contains a couple of Flash questions.
  3. Sample midterm 3     We did not cover the duality paper.


There is a class newsgroup, su.class.cs240, that can be used by members of the class to converse with each other. All course announcements will be put on to the class web page. The news group is a good place to advertise for study groups, ask questions of other students, etc.

Course Outline

This course makes no attempt to cover all the interesting topics in operating systems. Instead, we will cover a few topics in depth. The course is divided into the following general topic areas:

Virtual memory management
Discussions of virtual memory management implementations and recent work in virtual memory for multiprocessors, NUMA machines, large virtual address spaces, and other topics.
Synchronization and communication
Discussions of synchronization with an emphasis on monitors. Communication using remote procedure call.
File systems
Discussions of file system interfaces and disk storage management techniques.
Protection and security
Discussions of data security and authentication.
Extensions and fault tolerance
Discussions of mechanisms for implementing OS services at user level, OS structure and performance, reliability and availability of OS services.
History and experience
Historically important papers and experience reports by senior researchers in the field.

Reading List

Category/Date Title Author(s)
(1/8) The Rise of "Worse is Better" Richard Gabriel
Conc. (1/10) An Investigation of the Therac-25 Accidents Leveson and Turner
Conc. (1/13) Eraser: A Dynamic Data Race Detector for Multithreaded Programs Stefan Savage
Conc. (1/15) Experience with Processes and Monitors in Mesa Butler Lampson
Conc. (1/17) Scheduler Activations Anderson, Bershad, Lazowska, and Levy
(1/20) Observance of Martin Luther King Day (holiday, no classes)
VM (1/22) Virtual Memory Management in the VAX/VMS Operating System Levy and Lipman
VM (1/24) Practical, Transparent, Operating System Support for Superpages Navarro, Iyer, Druschel, and Cox
VM (1/27) Memory Resource Management in VMware ESX Server Waldspurger
VM (1/29) Simple But Effective Techniques for NUMA Memory Management Bolosky, Fitzgerald, and Scott
(1/31) Review session for midterm
(2/3) First midterm
N/W (2/5) Flash: An Efficient and Portable Web Server Pai, Druschel, and Zwaenepoel
N/W (2/7) Eliminating Receive Livelock in an Interrupt-Driven Kernel Mogul and Ramakrishnan
N/W (2/10) Ethernet: Distributed Packet Switching for Local Packet Networks Metcalfe and Boggs
N/W (2/12) End-To-End Arguments in System Design Saltzer, Reed, and Clark
FS (2/14) Design and Implementation of the Sun Network File System Sandberg, Goldberg, Kleiman, Walsh, and Lyon
(2/17) Observance of Presidents' Day (holiday, no classes)
FS (2/19) The Anatomy of a Large-Scale Hypertextual Web Search Engine Brin and Page
FS (2/21) The Design and Implementation of a Log-Structured File System Rosenblum and Ousterhout
FS (2/24) Deciding When to Forget in the Elephant File System Santry et. al.
FS (2/28) A Low-Bandwidth Network File System Muthitacharoen, Chen, and Mazieres
FS (3/3) A Case for Redundant Arrays of Inexpensive Disks (RAID) Patterson, Gibson, and Katz
(3/5) No classes
(3/7) Second midterm
Experience (3/10) Disco: Running Commodity Operating Systems on Scalable Multiprocessors Bugnion, Devine, Govil, and Rosenblum
Experience (3/12) Application Performance and Flexibility on Exokernel Systems Kaashoek, Engler, and others
Experience (3/14) The Cathedral and the Bazaar Raymond

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