Course Syllabus

Logistics

This is for CS 450, Fall 2022. Lecture is MW 1:50PM-3:05PM in SB104.

Course Overview

Operating systems run the world. Without an OS, you couldn’t have hundreds of programs running at once, you’d have to have deep understanding of hardware, and you’d have to rewrite your code for each new machine on the market. You wouldn’t have web servers, desktop machines, laptops, phones, or smart watches; no Siri, no Alexa, no TensorFlow or CUDA programs.

In this course, you will dive straight into the deepest and often most confounding component of a computer system’s software stack. You will become familiar with both the high-level concepts underpinning modern operating systems and with low-level mechanisms, in addition to new and emerging techniques and programming models for computer systems. I am a strong believer in learning by doing, so the majority of your time for this course will be spent working on programming projects, both very low-level work and high-level (user-space) work. This course will be challenging! It will bring together a lot of concepts you’ve learned in your previous courses, from data structures and algorithms to assembly language, computer architecture, virtual memory, and advanced C programming.

Course Goals

My goal with this course is for you to be exposed to and become familiar with the following: - Operating system architectures and design trade-offs - Programming patterns and sound programming principles for large software systems - Virtual memory and resource virtualization - Principles underlying the distinction between policy vs. mechanism - Principles of End-to-end systems design - Concurrency and Safety - Concurrency vs. Parallelism - Practical debugging - I/O Devices - File Systems - Persistence - Non-volatile memories and emerging technologies - Future OS directions and trends

Topics

1. Computer architecture review (3 hours)
2. Virtualization Foundations and Theory (3 hours)
3. Full System Emulation (6 hours)
4. Process Virtual Machines (4 hours)
5. High-level Language Virtual Machines (9 hours)
6. System Virtualization (9 hours)
7. Virtual Machine Management (3 hours)
8. Network Virtualization (3 hours)
9. Lightweight Virtualization and Containers (3 hours)
10. Virtualization Performance and Optimizations (1.5 hours)
11. Current and Future directions (1.5 hours)

Course Outcomes

• Define the functionality that modern operating systems must provide.
• Articulate design trade-offs inherent in operating system design.
• Understand the benefits of software modularity and how it applies to OS design.
• Understand the importance of concurrency and how to implement concurrent abstractions correctly in an OS.
• Understand OS scheduling policies and mechanisms (for execution contexts, I/O).
• Understand the benefits and applications of resource virtualization, and how it is achieved by the OS.
• Understand how operating systems implement protection, isolation, and access control.
• Understand the fundamentals of data storage, including file abstractions, file systems, object storage, etc.
• Understand how OSes employ caching in various ways to improve performance, and how this impacts system complexity.
• Understand and apply programming patterns for efficient systems implementation.

Prerequisites

You must have taken CS 350 and CS 351. I will only waive this requirement in truly exceptional cases—this will be a challenging course, and you will need to already be quite familiar with the fundamentals of computer systems. You should be comfortable (ideally proficient) with programming in C. I won’t take much time to cover basic C programming.

Lectures

It is critical you attend class sessions.

Textbooks

We will be referring to two textbooks for this course. Both are freely available online. We will be using Remzi and Andrea Arpaci-Dusseau’s Operating Systems: Three Easy Pieces (OSTEP) and the RISC-V xv6 book.

Readings

For every lecture, I will be posting required readings on the course webpage, mostly from the OSTEP and xv6 books, but also from other sources. Be sure to read them! If a reading is marked as required, the reading content is fair game for exams. Any readings I post that are required will be freely available either from the web or from me. I may post optional/extra reading as well. These may play into any extra credit I choose to include on exmas.

Projects

By far the most important part of this course is the projects. You will learn by doing. Thus, they will comprise the lion’s share of your grade. Unless otherwise noted you will be working individually on projects. Projects will be generally due at 11:59PM CST on the due date. You can submit as many times as you like (make handin) until then. Your project grades will be calculated based on the output of make grade, and all labs will be weighted equally.

Collaboration

See the section on academic integrity.

DO NOT publish your solutions to publicly accessible websites like Github, Gitlab or publicly visible file servers.

Bad Submissions

If you submit the wrong file or a program that doesn’t compile or doesn’t run at all, or one which does not pass any tests, you will earn a zero for that project. It is your responsibility to make sure that you submit what you intend to submit and that you submit a well-formed, compiles-without-errors codebase. In some cases we will include a suite of tests for you to verify your work.

Grading

The grade break-down for the semester is as follows:

• 70% Projects
• 10% Midterm Exam
• 15% Final Exam
• 5% In-Class Participation

Letter Grade Cut-offs

• A: 90-100
• B: 80-89
• C: 70-79
• D: 60-69
• E: 0-59

Grading Policies

Borderline Grades

Roughly nine times out of ten, there’s no ambiguity as to what your Final Grade is; the only judgement comes in at the borders. I will look for every reason I can find to push you up to the next higher grade, such as: Your Final Exam score is much higher than the average, or your Final Exam score is higher than your earlier test scores. In addition, if you’re two points short on the Final Exam, I’ll give you the benefit of the doubt. On the other hand, if you’re five points short, you get the lower grade.

Grading Principles

The Final Grade describes the overall quality of your semester’s work: It all gets piled onto a big scale and my job is to tell you what the Quality meter says.

For figuring out Final Grades, there are two ethical/professional principles I must follow. Violating these principles would be unethical and unprofessional of me and it would cheat the other students.

First principle: Grades can be based only on the quality of your work. So unfortunately, you can work hard for the course but still earn a low grade. I’m sorry if a low grade makes your life harder, but that’s absolutely not a reason to raise your grade.

The second principle: Grading has to be done on a level playing field: I can’t give one person an opportunity that I don’t offer to everyone unless it’s to re-level the playing field. This is why questions like “Can I retake the test or can you give me some extra work to raise my grade?” have the answer “No.”

Late work policy

Each of you will have a total allocation of 96 late hours for the entire course. These only apply to the projects (not the exams). You can use these hours however you want, but be aware of your current quota. For example, if you submit a project 2 hours late, you will have 94 late hours remaining. If you submit 4 days late for one project, that will use up all of your late hours. After you’ve exhausted your late hours, your grade will be penalized. Beyond that point, one hour late is the same as one day late.

After you’ve run out of free late hours, for all projects, you can submit up to three days late with penalties. Each day you will be docked 10%. So if I have a perfect project, submitting three days late will give me 70%. After three days, submissions will no longer be accepted, and you will receive a zero for that project.

If you have an emergency or are ill, it may be possible to excuse you from a project or to get you an extension, but you must contact me (or have a friend or family member contact me) as soon as you can. Please don’t wait until you get well / get back into town / start worrying about your Final Grade. Overly delayed requests may be denied. Requests made after classes end will be denied.

Exams

There will be two exams, a midterm and a final exam.

Makeup Exams

If you can’t make it to an exam because you’re sick or have an emergency, it may be possible to get you a makeup exam, but contact me (or have a friend or family member contact me) as soon as you can. Overly delayed requests may be denied, so don’t wait until you get well / get back into town / start worrying about your Final Grade. Requests made after classes end will be denied.

Make-up exams are not a guaranteed right, especially if you ask after the exam. Barring some urgent reason, you must take tests at the scheduled time (Getting a cheaper airline ticket is not considered to be an urgent reason).

If during the test, you feel too ill to finish it, stop and come up and talk to me so we can work on rescheduling it; don’t turn in the test and then come to me later. Similarly, don’t turn in the Final if you want a grade of Incomplete.

Regrades

If you think a test or project has been misgraded, then if a TA graded it, discuss it with that TA first. If you still think it’s been misgraded, discuss it with me. Regrade requests must be specific: Don’t just ask us to regrade an entire problem or assignment. Also, you must include your justification for a higher grade: Don’t just say you think you deserve more points. Regrade requests should be timely, else they may be denied. In particular, regrade requests made after classes end will be denied.

Disability Accommodations

Reasonable accommodations will be made for students with documented disabilities. In order to receive accommodations, students must obtain a letter of accommodation from the Center for Disability Resources. The Center for Disability Resources (CDR) is located in Life Sciences Room 218, telephone (312) 567-5744 or disabilities@iit.edu.

Sexual Harassment and Discrimination Information

Illinois Tech prohibits all sexual harassment, sexual misconduct, and gender discrimination by any member of our community. This includes harassment among students, staff, or faculty. Sexual harassment of a student by a faculty member or sexual harassment of an employee by a supervisor is particularly serious. Such conduct may easily create an intimidating, hostile, or offensive environment.

Illinois Tech encourages anyone experiencing sexual harassment or sexual misconduct to speak with the Office of Title IX Compliance for information on support options and the resolution process.

You can report sexual harassment electronically here, which may be completed anonymously. You may additionally report by contacting the Title IX Coordinator, Virginia Foster at foster@iit.edu or the Deputy Title IX Coordinator at eespeland@iit.edu.

For confidential support, you may reach Illinois Tech’s Confidential Advisor at (773) 907-1062. You can also contact a licensed practitioner in Illinois Tech’s Student Health and Wellness Center at student.health@iit.edu or (312)567-7550

For a comprehensive list of resources regarding counseling services, medical assistance, legal assistance and visa and immigration services, you can visit the Office of Title IX Compliance website.

Academic Integrity

In short: DO NOT CHEAT! Why would you do that? You’re paying for this, so you might as well get something out of it. All students are responsible for maintaining the highest level of academic integrity, as discussed in the IIT Code of Academic Honesty The normal penalty for violations of this policy, especially copying or other cheating during tests, is an E for the course, plus notification of the student’s advisor and/or department and any appropriate administrators.

You are allowed to discuss your work with others in the class (we especially encourage you to do this on Diderot), but ultimately what you submit must be solely yours. Cheating, plagiarism, copying from other students, or any other sort of academic dishonesty may result in you getting a zero on the assignment, may impact your grade negatively, and may result in referral to the Dean.

Disability Accommodations

Reasonable accommodations will be made for students with documented disabilities. In order to receive accommodations, students must obtain a letter of accommodation from the Center for Disability Resources. The Center for Disability Resources (CDR) is located in Life Sciences Room 218, telephone (312) 567-5744 or disabilities@iit.edu.

Sexual Harassment and Discrimination Information

Illinois Tech prohibits all sexual harassment, sexual misconduct, and gender discrimination by any member of our community. This includes harassment among students, staff, or faculty. Sexual harassment of a student by a faculty member or sexual harassment of an employee by a supervisor is particularly serious. Such conduct may easily create an intimidating, hostile, or offensive environment.

Illinois Tech encourages anyone experiencing sexual harassment or sexual misconduct to speak with the Office of Title IX Compliance for information on support options and the resolution process.

You can report sexual harassment electronically here, which may be completed anonymously. You may additionally report by contacting the Title IX Coordinator, Virginia Foster at foster@iit.edu or the Deputy Title IX Coordinator at eespeland@iit.edu.

For confidential support, you may reach Illinois Tech’s Confidential Advisor at (773) 907-1062. You can also contact a licensed practitioner in Illinois Tech’s Student Health and Wellness Center at student.health@iit.edu or (312)567-7550

For a comprehensive list of resources regarding counseling services, medical assistance, legal assistance and visa and immigration services, you can visit the Office of Title IX Compliance website.