CSE 120: Principles of Computer Operating Systems

Spring 2023

Mon, Wed, Fri 2–2:50pm (PCYNH 106)
Discussion Session
Wed 5–5:50pm (PCYNH 106)
Yiying Zhang (yiying@ucsd.edu)
Office Hours: Mon noon-1pm (CSE 3124)
TAs and Tutors
Kaiyuan (Kyle) Wang (TA) k5wang@ucsd.edu
Fengyuan Wu (TA) fwu@ucsd.edu
Steven Wu (TA) s2wu@ucsd.edu
Charlotte Tang (TA) yit015@ucsd.edu
Yunxiang Chi (Tutor) yuchi@ucsd.edu
Yuke Liu (Tutor) yul063@ucsd.edu
Xiyan Shao (Tutor) x3shao@ucsd.edu
TA/Tutor Lab Hours
Discussion Board
Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dusseau
Operating Systems: Three Easy Pieces
Version 1.00   (Available free online!)

Course Objectives

This course covers the principles of operating systems. It emphasizes the basic concepts of OS kernel organization and structure, processes and threads, concurrency and synchronization, memory management, file systems, and communication. It is also a project course, providing essential experience in programming with concurrency, implementing and unmasking abstractions, working within an existing complex system, and collaborating with other students in a group effort.

Course Schedule

The following table outlines the tentative schedule for the course. We will update it as the quarter progresses. The optional readings include primary sources and in-depth supplements for concepts in the class. Supplemental reading is for your own interest — the readings are not required, nor will you be tested on the material. Note that some of the links to the documents point to the ACM Digital Library. UCSD has a subscription to the ACM Digital Library, so you will need to use a web browser on campus to access them.

Date Lecture Readings Optional Homework Project
4/3 Course Intro CH. 1      
4/4 (Tuesday)     HW 1: Out   PR 0: Out  
4/5 Intro to OS CH. 2 The Structure of the 'THE'-Multiprogramming System
The UNIX Time-Sharing System
4/7 Interaction between hardware, OS, and applications CH. 6 Linux context switch
A Case Against (Most) Context Switches (HotOS'21)
4/10 Timer Interrupts, Processes CH. 4, CH. 5 A fork() in the road (HotOS'19)    
4/11 (Tuesday)       PR 0: Due
PR 1: Out
4/12 Process Creation CH. 26 POSIX Threads Programming  
4/14 Threads CH. 27 Illustrated Tales of Go Runtime Scheduler
C++ Coroutine Tutorial
4/17 Synchronization CH. 28    
4/18 (Tuesday)     HW 1: Due
HW 2: Out
4/19 Synchronization Primitives CH. 29 RCU Usage In the Linux Kernel: One Decade Later (Linux RCU lock)    
4/21 Conditional Variables CH. 30 Monitors: An Operating System Structuring Concept    
4/26 Semaphores CH. 31      
4/27 (Thursday)       PR 2: Out
4/28 Concurrency Bugs CH. 32 Understanding Real-World Concurrency Bugs in Go (ASPLOS'19)    
5/1 Midterm Review      
5/2 (Tuesday)     HW 2: Due
HW 3: Out
PR 1: Due
5/3 Midterm Exam 7pm - 8:50pm (Ledden Auditorium)      
5/5 Memory Management Overview CH. 15, CH. 16,    
5/8 Paging CH. 18, CH. 19, CH. 20    
5/10 TLB, Swapping CH. 21      
5/12 Memory Allocation and Sharing      
5/15 CPU Scheduling CH. 7, CH. 8 Lottery Scheduling (OSDI'94)
Shenango: Achieving High CPU Efficiency for Latency-sensitive Datacenter Workloads (NSDI'19) 
5/16 (Tuesday)       PR 3: Out
5/17 Page Replacement CH. 22,    
5/19 Storage Devices CH. 37, PR 2: Due  
5/22 File System Overview CH. 39, A File is Not A File (SOSP'11)  
5/23 (Tuesday)     HW 3: Due
HW 4: Out
5/24 File System Disk Layout CH. 40    
5/26 FFS and Buffer Cache CH. 41    
5/29 Memorial Day - No Class    
5/31 File System Reliability CH. 42 IRON File System (SOSP'05)    
6/2 Distributed Systems and Data Centers CH. 48    
6/5 Cloud and Virtualization Berkeley View of Cloud Computing    
6/6 (Tuesday)     HW 4: Due  
6/7 Systems and Machine Learning    
6/9 Final Review    
6/10 (Saturday)       PR 3: Due
6/14 Final Exam 3pm - 5pm (PCYNH 106)      

Course Organization

The course is organized as a series of lectures by the instructor, discussion sections by the TAs, reading, homework, and project assignments, and exams:


The course will have four homeworks. I will post them as the quarter progresses. You will submit all your homework electronically via Canvas. We will reduce homework grades by 20% for each day that they are late.

Due to extensive copying on homeworks in the past, we have changed how homeworks are graded. As long as you submit a technical answer related to the question, you will get full credit for the question. The goal of the homeworks is to give you practice learning the material. The homework questions both supplement and complement the material from lecture and in the project, and you will also find the homework questions to be useful for practicing for the exams. We will post solutions to all homeworks after they are submitted, and you can use them for studying as well. But, even with the solutions, the amount you learn from the homeworks will be directly correlated with your effort working on them.

I encourage you to collaborate on the homeworks: You can learn a lot from your fellow students. Collaboration consists of discussing problems with other students and independently writing your own answers to the problems based upon those discussions. As a rule of thumb, you should be able to discuss a homework problem in the hall with others, go home, and then write up your answer to the problem on your own.

  • Homework 1
  • Homework 2
  • Homework 3
  • Homework 4
  • Projects

    The course has one tutorial project and three programming projects using the Nachos instructional operating system.


    The course has two exams, a midterm and a final. The midterm will cover the first half of the class, and the final will cover the second half of the class.

    Discussion Sections

    Discussion sections answer questions about the lectures, homeworks, projects, and programming environment. They may also supplement the lectures with additional material.


    Your grade for the course will be based on your performance on the homeworks, midterm exam, final exam, and projects, as follows.

    The academic honesty guidelines outlined by Charles Elkan apply to this course. I urge you to resist any temptation to cheat, no matter how desperate the situation may seem. If you are in circumstances that you feel compel you to cheat, come to me first before you do so.