CS240: Advanced Topics in Operating Systems

Winter 2002 -- Dawson Engler

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.

Important Dates

Section 1: MWF 2:15-3:05 in Skilling Auditorium (televised)
Section 2: MWF 3:15-4:05 in Bldg. 380, room 380Y

Course Staff


Dawson Engler
Office: 314 Gates
Telephone: (650) 723-0762
E-mail: engler@cs.stanford.edu
Office hours: MWF 4-5pm. Also, other times by appointment.

Teaching Assistants

Andy Chou
E-mail: acc@cs.stanford.edu
Office hours: Thursday 1:30-5:00pm at Gates 506, and by appointment
Sergio Marti
E-mail: smarti@stanford.edu
Office hours: Tuesday 1:00-5:00pm at Gates 506

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-staff@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-students@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-guests mailing list by emailing majordomo@lists.stanford.edu with the body of the message saying "subscribe cs240-guests."

SITN Contacts


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, pop quizzes, 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.

For every paper discussion two students will be pre-selected as scribes for the discussion. The scribes will be responsible for writing summaries of the paper and the class discussion. The two scribes will then be given a week to combine their summaries and include any additional helpful information, for example pointers to additional related reading material. These summaries should then be emailed to the staff who will put them up on the website as lecture notes.


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. Since it is difficult for SITN students to participate in class discussion, they will be instead responsible for writing a 2-3 page paper summary every two weeks (roughly 5 in total). 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 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!

SITN students may take the exams at their company sites, but the exams must be taken at the same time as the in-class exams. Please make sure that you'll be able to take the exams as scheduled.

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.


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.