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CS377: Operating Systems

Lecture 1 Course Introduction

Fall 2025

Instructor: Nikko

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A hearty welcome to all of you!

We, the staff for this course, support the UMass commitment to diversity.

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Our plan today:

  • Why study OS?
  • A bit about us ...
  • CS 377: 10,000 ft view
    • What did you get yourself into?
    • Grading policy
  • Our expectation from you
    • Can I use ChatGPT/GenAI tools?
  • Q&A

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Why Study OS?

Hilariously: You are unlikely to get a job building an OS...

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Why Study OS?

Hilariously: You are unlikely to get a job building an OS.

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Why Study OS?

Hilariously: You are unlikely to get a job building an OS.

However, Understanding operating systems will enable you to utilize your computer more effectively.

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Why Study OS?

Hilariously: You are unlikely to get a job building an OS.

However, Understanding operating systems will enable you to utilize your computer more effectively.

Why does my application run slowly?

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Why Study OS?

Hilariously: You are unlikely to get a job building an OS.

However, Understanding operating systems will enable you to utilize your computer more effectively.

Why does my application run slowly?

How can I make my application cheaper to run?

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Why Study OS?

Hilariously: You are unlikely to get a job building an OS.

However, Understanding operating systems will enable you to utilize your computer more effectively.

Why does my application run slowly?

How can I make my application cheaper to run?

It will also serve as an excellent example of system design issues whose results and ideas you will apply elsewhere.

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Journey, you will pick up multiple skills along the way

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CS 377 teaching team

Who are we?

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About “us”: Instructor, TAs, UCAs

Phuthipong Bovornkeeratiroj

New(?) teaching faculty

(just graduated last semester),�interested in climate change, human-centered design.

“Nikko” (he/him)

Instructor

Nathan Kwan-Ho Ng

(he/him)

Teaching Assistant

nth year PhD student.

TAed for 677 and 532 multiple times, distributed systems (edge computing) researcher

Hetvi Shastri

(she/her)

Teaching Assistant

TA'ed 230, 677

Research area: Distributed Systems and Machine Learning

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About “us”: Instructor, TAs, UCAs

We are all here to help you learn!

Hoa La

(he/him)

UCA

Tuan Nguyen

(he/him)

UCA

Fun fact: I like concurrency bugs

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CS 377 course info

What did you get yourself into?

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A Day in the Life with 377 (probably)

“I think I’m going to drop this course”�(Nikko: please no!)

Credit: Bruno Portela

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Big picture (10,000 ft. view)

Tools

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Canvas�class materials, quizzes, assignments

Poll Everywhere�in-class activities

Zoom�only for online office hours

Piazza�Q&A, discussions, announcements

Gradescope�submit assignments, re-grading requests

Echo360�class records (only lectures, not labs)

Course Elements

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In-person

Assignments

  • Twice a week lectures
  • Once a week lab
  • Optional Exam(s)
  • 10 Quizzes
  • 11-12 Lab assignments
  • 5 Projects

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Course Evaluation (Grades)

In-person

Assignments

  • Twice a week lectures
  • Once a week lab
  • Optional Exam(s)
  • 10 Quizzes
  • 11-12 Lab assignments
  • 5 Projects

80%

20%

4 pick 2! (10% each)

Attendance

Final Exam

Oral Exam

Group Project

20%�20%�40%

Assessing mastery of material, avoiding “high-stakes” setting:

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Grade Letter & Range

A

93 or more

A-

90-92

B+

87-89

B

83-86

B-

80

C+

77

C

73

C-

70

D+

67

D

60

F

59 or less

Any decimals will be rounded up.

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What’s “4 pick 2”?

20%

4 pick 2!

Attendance

  • Lectures + Labs
  • Absence
    • 0-5 classes -> 100%
    • 6 classes -> 90%
    • 7 classes -> 80%, and so on.

Final Exam

  • In-person, closed-book & notes
  • At least 70% comes from quizzes, labs, in-class questions.

Oral Exam

  • Low stress, job interview style exam.
  • Three levels - easy, medium, difficult
  • More details mid-semester

Group Project

  • 1-3 students/group
  • Pick one of the topics related to OS.
  • Runnable program + test cases + video record

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Q: Can I pick all 4? �A: Yes, but only the highest two count.

you might feel like you are drinking from a fire hydrant!

Example:

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  • Attendance - 6%
  • Final Exam - 8.5%
  • Oral Exam - 9%
  • Group Project - 10%

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Total: 10+9 = 19%

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Attendance

  • Lectures + Labs (PollEverywhere, Headcount.live)
  • Absence
    • 0-5 classes -> 100%
    • 6 classes -> 90%
    • 7 classes -> 80%, and so on.
  • Once in a while, we check-in with papers to double check.

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Final Exam (10%)

  • In-person
  • Closed-book, closed-notes
  • At least 70% comes from quizzes, labs, in-class questions.

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Oral Exam (10%)

  • Low stress, job interview style exam.
  • Three levels - easy, medium, difficult
  • We will provide more details and examples mid-semester

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Group Project (10%)

  • Upto 3 students/group
  • Pick one of the topics related to Operating Systems and implement it.
  • Runnable program + test cases + presentation (last class)
  • We will provide more details and examples @ week 3

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Question: Which “4 pick 2” options do you prefer?

Let’s test the poll

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Course Evaluation (Grades)

In-person

Assignments

  • Twice a week lectures
  • Once a week lab
  • Optional Exam(s)
  • 10 Quizzes
  • 11-12 Lab assignments
  • 5 Projects

80%

20%

4 pick 2! (10% each)

Attendance

Final Exam

Oral Exam

Group Project

20%�20%�40%

Assessing mastery of material, avoiding “high-stakes” setting:

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(20%) Quizzes

  • There are 10 quizzes.
  • Quizzes will test your knowledge of the material.
  • They will be multiple choice, true/false, etc.
  • You may take them as many times as you want before the deadline.
  • You have approximately a week to complete a quiz.

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The first quiz will be assigned next Friday (Feb 12) and due on (Feb 19)

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(20%) Lab Exercises

  • A lab exercise is a short activity that will focus on expanding your knowledge in a particular topic area.
  • They are often designed to provide guidance for an upcoming project or to enhance your understanding of the content for that week.
  • They are completed by submitting to Gradescope.
  • They are graded both automatically and sometimes manually.

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The first lab is this Friday, let’s warm up with basic C.

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(40%) Project Assignments

  • There are 5 projects that are hands on with programming as it relates to the material.
  • You will be provided a “starter” project, but will require additions, modifications, or tasks to complete it.
  • Most projects come with some tests (but not all) to guide you.
  • You submit your projects to Gradescope which will run our auto-grader and apply additional private tests.

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Your submission is your work. No exceptions.

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(40%) Project Assignments

  • Late Policy:

Early bird submission

Late submission

Resubmission

Hidden test cases become public

Release date

3 days

= no penalty

4 days �= 0.8*score

Due date

bonus credit

= +0.2%

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Bonus credits (max. 3%)

  • Early bird submission (0.2% per project = 1% in total)
  • Bonus discussion topics on Piazza (0.2% per topic)
  • Bonus readings on Piazza (0.2% per paper)
  • Two questionnaire at the mid and end of semester. (0.5% each)
  • Brownie points
    • Help make this course better. (suggestion, feedback, etc)
    • Help your friends in the course. (piazza, class note, etc)
    • But you have to let us know! submit what you did using the brownie points form on Canvas.

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377 Squid Game Day

  • One class.
  • Some fun activities with some prizes.
  • Make friends, compete, cooperate.

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Miscellaneous

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Prerequisites

Major Applicability

  • COMPSCI 230 Computer Systems Principles
  • Or equivalent background
  • This course counts as a 300-level Computer Science Major elective.

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Textbook

Operating Systems: Three Easy Pieces, Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dussea.

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This is a free textbook available online. While the entire textbook is available for free from this site, if you so wish, a hard copy may be purchased on Amazon.

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This book is absolutely fabulous as far as OS books go.

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Class policy

Our expectation from you

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We can’t learn without making mistakes!

The goal is to learn and enjoy the process here on out.

Some snacks for participating in class activity/discussion.

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Course norm

  • Communicate respectfully with all course participants and teaching staff.

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  • Remember that this is a GLOBAL community.�People may have very different lived experiences than you. Keep an open mind, and be empathetic.

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  • Our goals:
    • learn a lot
    • have fun!

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ChatGPT/AI policy

Let the AI teach you.

Let the AI give you feedback.

Let the AI do your assignments.

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Cheating policy

Warning: We will compare your code with all previous years submissions too!

  • First offense: a 0 on the assignment.
  • Second offense: an F in the course.

Please don’t cheat. We take this seriously.

Please ask for extension & support instead!!!

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Syllabus

  • The syllabus is available on the course website
  • The syllabus is the primary resource for all details regarding the course
  • You should consult the syllabus for all aspects of the course
  • There may be circumstances where the syllabus needs to be updated, so always visit the syllabus online to ensure you are reading the most updated information.

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Software Tools

We will use a variety of software tools in this course. The most important that you will need to install on your computer is:

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  • Visual Studio Code (VSCode)

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You will be doing all your coding in the Edlab environment. The Edlab environment is a cluster of Linux machines with all the installed software that you need.

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You can use VSCode to remotely connect to the Edlab and code like you are on your own machine. Very nice!!

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Or you can optionally use emacs, vim, or nano.

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Academic Honesty and Collaboration Policy

Project Assignments: Individual work, no code sharing

  • Collaboration allowed, but not sharing solutions
  • Cheating consequences, see Academic Misconduct Penalties

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Collaboration in Labs

Labs: Collaborative work in groups

  • Submit as a group on Gradescope
  • Open discussions encouraged but within groups
  • Sharing solutions with other groups not allowed
  • Consequences outlined in Academic Misconduct Penalties

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Academic Misconduct Penalties

Penalties: Consequences for academic misconduct

  • First offense: 0 on assignment, 0 on scores
  • Second offense: F in the course
  • These are both informal resolutions

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A formal resolution may lead to suspension or expulsion

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Contact and Resolution

Contact: Suspicion of misconduct leads to email contact

  • Dialog initiated for resolution discussions
  • Formal resolutions may involve harsher punishments

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/* */ || ?

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Why do we need an OS?

Assigned video (please watch it before next class):

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What’s an OS?

Interface between the user and the machine architecture.

Implements a virtual machine that is (hopefully) easier to program than raw hardware.

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What’s an OS?

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User-level Applications

Operating System

Hardware

virtual machine interface

physical machine interface

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Most Important Features

Services: The OS provides standard services (the interface) which the hardware implements.

  • File system, virtual memory, networking, CPU scheduling, and time-sharing

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Most Important Features

Services: The OS provides standard services (the interface) which the hardware implements.

  • File system, virtual memory, networking, CPU scheduling, and time-sharing

Coordination: The OS coordinates multiple applications and users to achieve fairness and efficiency (throughput).

  • Concurrency, memory protection, networking, and security.

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Most Important Features

Services: The OS provides standard services (the interface) which the hardware implements.

  • File system, virtual memory, networking, CPU scheduling, and time-sharing

Coordination: The OS coordinates multiple applications and users to achieve fairness and efficiency (throughput).

  • Concurrency, memory protection, networking, and security.

Goal: Design an OS so that the machine is convenient to use (a software engineering problem) and efficient (a system and engineering problem).

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Next class: Introduction to Operating Systems

There is a body of software that is responsible for making it easy to run programs.

Allowing programs to share memory…

Enabling programs to interact with devices…

… and other fun stuff like that!

This body of software is called� the operating system (OS).

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Class 1: Wrap up

  • Course overview
  • Why study OS?
  • What is OS?

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Notable (your to do’s):

  • Check out our class syllabus.
  • Check out our class Canvas.
  • Join Piazza & Gradescope, if you haven’t.
  • Watch the assigned video.
  • The first lab is this Friday!

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ADJOURN

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Old slides

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About “us”: Instructor, TA, UCAs

Phuthipong Bovornkeeratiroj

New teaching faculty,

originally from Thailand, �interested in climate change, human-centered design.

“Nikko” (he/him)

Instructor

Dave Dirnfeld

(he/him)

Teaching Assistant

TA’ed 377 for 8 times,

created multiple labs and assignments,

computer vision researcher.

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About “us”: Instructor, TA, UCAs

We are all here to help you learn!

August Huber

(he/they)

Head UCA

Neha Aryasomayajula

(she/her)

UCA

Sagnik Pal

(he/him)

UCA

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About “us”: Instructor, TAs, UCAs

Phuthipong Bovornkeeratiroj

New teaching faculty,

originally from Thailand, �interested in climate change, human-centered design.

“Nikko” (he/him)

Instructor

Dave Dirnfeld

(he/him)

Teaching Assistant

TA’ed 377 for 8 times,

created multiple labs and assignments,

computer vision researcher.

David Gerard

(he/him)

Teaching Assistant

MS student graduating this Spring, previous undergrad, software engineer at MITRE, enjoys driving up to Vermont to ski on weekends.

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About “us”: Instructor, TA, UCAs

We are all here to help you learn!

Khiem Le

(he/him)

UCA

Neha Aryasomayajula

(she/her)

UCA

Sagnik Pal

(he/him)

UCA