General Information and Syllabus

Based on a document by Julie Zelenski, Cynthia Lee, and others
Last updated October 6, 2021

Instructor: Nick Troccoli (troccoli @
Helper Hours on helper hours calendar
All course staff: See front page
Course staff email:

Course Essentials

  • The class website for CS107 is located at Please regularly check the course website as we will post important announcements there, as well as the course schedule, lecture materials, handouts, assignments, and more.

  • We will be using Canvas to host videos and lecture quizzes. Access our Canvas course.

  • We will have live lecture on Mondays and Fridays, 1:30PM - 3PM in Bishop Auditorium. You are responsible for completing pre-lecture material on Canvas prior to live lecture, and live lecture will be dedicated to review and additional exercises. (Note: you do not need to complete anything for Lecture 1). Read about lecture.

  • The discussion forum on Ed is the place for students to ask questions and discuss course topics with peers and staff. Visit helper hours if you have more specific debugging or conceptual questions.

  • The myth servers are our remote workspaces for completing programming assignments. Read more in our getting started guide

Course Overview

CS107 is the third course in Stanford's introductory programming sequence. The CS106 courses provide you with a solid foundation in programming methodology and abstractions, and CS107 follows on this to build up and expand your breadth and depth of programming experience and techniques. The course will work from the C programming language down to the microprocessor to de-mystify the machine. With a complete understanding of how computer systems execute programs and manipulate data, you will become a more effective programmer, especially in dealing with issues of debugging, performance, memory, and robustness. Topics covered include: the C programming language, data representation, machine-level code, computer arithmetic, elements of code compilation, optimization of memory and runtime performance, and memory organization and management.


CS107A, also called Pathfinders (or ACE), is a supplementary instruction program that meets for a weekly section and holds Pathfinders-specific review sessions. CS107A is application-only; please see the FAQ page for more information.


The prerequisite for CS107 is CS106B/X (or equivalent). You should have practical C/C++ skills using recursion, dynamic data structures (pointers, linked lists, trees, graphs), data abstraction, classic data structures (lists, stacks, queues, sets, maps), and standard algorithms (searching, sorting, hashing). You should have an appreciation of the intrinsic value of good engineering and design and you will be expected to produce well-decomposed, readable code. Come talk with us if you need help determining the right placement for you.


If you are a matriculated Stanford graduate student, you may enroll in CS107 for 3-5 units based on your schedule. Otherwise, you are required to enroll in CS107 for 5 units. Taking the course for reduced units does not alter the course requirements.

Guiding Principles For Fall 2021

We are each starting the 2021-22 academic year in unique circumstances, likely not fully recovered or restored from the stresses of the past 18 months and now facing new uncertainties, responsibilities, and emotions. Especially under such conditions, we appreciate your participation in CS107, and we will do everything we can to support you. We have designed the course to the best of our ability to provide flexibility. There are campus resources, such as accommodations, undergraduate advising directors, well-being coaches, counselors, academic coaches, Hume Center writing tutors, and the FLI opportunity fund for broader needs you might have. For information about specific policies and procedures for Fall 2021, Student Affairs has the most up-to-date information for students. If there are additional ways we can support you in the course, please feel encouraged to reach out to us. Without requesting or expecting details of your situation, we will do everything we can to ensure your course learning is productive and enjoyable.

Course Goals

The goals for CS107 are for students to gain mastery of

  • writing C programs with complex use of memory and pointers
  • an accurate model of the address space and compile/runtime behavior of C programs

to achieve competence in

  • translating C to/from assembly
  • writing programs that respect the limitations of computer arithmetic
  • identifying bottlenecks and improving runtime performance
  • working effectively in a Unix development environment

and have exposure to

  • a working understanding of the basics of computer architecture

Course Environment

In CS107, there will be significant programming assignments and you can expect to work hard and be challenged by this course. Your effort can really pay off - once you master the machine and advance your programming skills to the next level, you will have powerful mojo to bring to any future project! To make that happen for everyone, we strive to create an inclusive and equitable class. We further depend on you to help each other obtain excellence rather than mistaking Stanford or this class as zero-sum. We ask that you do your part by seeking to promote the success of others, and by treating each other in ways that respect and celebrate the diversity of talent that is drawn to our exciting field of Computer Science. Here are several aspects of our policy for creating an inclusive and equitable class:

  • Preparation: Perhaps more than many other subjects, students come to computer science with greatly varying previous exposure to the subject. Regardless of your background, as long as you meet the course prerequisites, you are well-prepared to succeed in CS107. Just ask the students who are now your TAs!

  • Classroom Environment: We are happy to answer questions you have through various course support channels (helper hours, discussion forum, etc.). However, during lectures, we request that any questions you ask be clarifications for yourself or others of the course material being discussed, rather than a question or comment intended to demonstrate additional knowledge beyond the scope of the current topic or the course, which may intimidate or discourage other students. If you do have such questions or comments, we are more than happy to discuss them during helper hours, or before/after any lecture!

  • Access and Accommodations: Stanford is committed to providing equal educational opportunities for disabled students. Disabled students are a valued and essential part of the Stanford community. We welcome you to our class. If you experience disability, please register with the Office of Accessible Education (OAE). Professional staff will evaluate your needs, support appropriate and reasonable accommodations, and prepare an Academic Accommodation Letter for faculty. To get started, or to re-initiate services, please visit If you already have an Academic Accommodation Letter, we invite you to share your letter with us. Academic Accommodation Letters should be shared at the earliest possible opportunity so we may partner with you and OAE to identify any barriers to access and inclusion that might be encountered in your experience of this course.

  • Name and Pronouns: We want you to be you in our class. You are always welcome to put your preferred name on all classwork and exams. If you have a name and/or pronoun that doesn’t match our registrar-provided class roster, please let us know and we will ensure that we use it in our class.

  • Course Expenses: If obtaining any material or resource for use in our class presents a financial hardship for you, please let us know and we will work with you to accommodate.

  • Feedback: Please do not hesitate to reach out to the course staff or the instructor, anonymously if you prefer (there is an anonymous feedback link on the main page of the course website), if any aspect of our course or community can be improved.

Course Structure

Course Grades

Final grades for the course will be determined using the following weights:

  • 45% Assignments
  • 15% Lab Participation
  • 10% Lecture Check-in Quizzes
  • 10% Midterm Exam
  • 20% Final Exam

Final course grades will be calculated by determining the raw overall score, and then breaking the score distribution into different letter grades. We do not decide these letter grade cutoff points until the end of the quarter, based on the course distribution - for that reason, we cannot guarantee in advance that a particular raw overall score will translate to a particular letter grade.

If you choose to take the course CR/NC, your final grade must be satisfactory or better--in other words, you need a C- or better to get a CR.


The main lecture material is pre-recorded as a collection of shorter videos that are posted on Canvas in advance of that actual lecture day.

  • Each video will have an associated lecture check-in quiz – a very short understanding check that will permit 3 attempts. You will have until 30 minutes before the start of the live lecture session to do these quizzes. The sum of lecture quizzes for each day is weighted equally (in other words, all quizzes combined for Lecture 2 are weighted the same as all quizzes combined for Lecture 3). No lecture quizzes will be accepted late.
  • Live lecture sessions will be optional and devoted to reviewing concepts further, answering questions, and doing additional exercises. All live lectures will be recorded and posted to Canvas afterwards.


In addition to lecture, you must also sign up for a weekly 1-hour 30-minute hands-on in-person lab led by one of our CAs. Each lab will have about 25-30 students, and in lab, students work in small groups on guided exercises. Labs encourage participatory collaborative learning - the goal is for everyone to come away with a clear understanding of the lab concepts and be prepared to go on to individually complete the assignments.

Part of your course grade comes from arriving on time, attending, participating in and completing the work in your lab each week. At the end of the lab, you will submit a checkoff sheet to record your lab participation / attendance grade. Arriving late or leaving early will result in not receiving lab credit.

You must submit your lab time preferences using a link posted on the main course webpage starting on Tue Sep 21 10:00 pm PDT. Note that signups are not first-come, first-serve; you may submit your preferences any time up to Sat Sep 25 5:00 pm PDT. You may also come back and update your preferences until this time as well. Our typical weekly schedule offers labs Tues, Wed, and Thurs at various times throughout the day. Labs begin the second week of classes. Note that you must sign up for labs via the course website (you do not sign up for labs on Axess).

If you cannot make your lab during a given week, you may attend a lab other than your assigned one as a "visitor". Visitors are accommodated when space is available, but priority is given to the assigned students. Please tell the lab TA at the beginning of your visiting lab that you are visiting so that they are aware and can place you in a lab group for that week. We strongly recommend attending your assigned lab where possible; students find that they learn best with a regular timeslot, the same lab TA, and a recurring lab group.

If you do have to miss attending the lab entirely, we strongly encourage you to work through the exercises for your own benefit, but there is no makeup credit for missed participation.


There will be seven assignments throughout the quarter, all of which are to be done individually. Assignments are due at 11:59pm PT sharp on the dates specified and are written and submitted electronically using the myth cluster of Unix workstations in the Gates Computer Science Building. These machines are accessible remotely from other machines such as your personal computer, and they are pre-installed with all software used for labs and assignments. Students edit, compile, and debug on the myth systems using a suite of open source development tools including gcc, make, gdb, and valgrind.

Assignments may consist of written portions and coding portions, and are graded and returned to you electronically via the course website. The course staff grades each programming portion on functionality (is the program’s behavior correct from an external perspective?) and style ("code review" - is the code clean, well-written and elegant?). Functionality is measured by how successfully the program executes on a comprehensive set of test cases. We create our test suite by working from the original program specification to identify a list of expected behaviors and write a test case for each. We use the autotester to run a submission on each test and award points for each successful result. Thus, the resulting functionality score is a direct reflection of how much observably correct behavior your program exhibited. This process is completely automated; the grader does not search your code to find bugs and deduct for them, nor do they appraise the code and award points for tasks that are attempted or close to correct.

The total number of points for an assignment is noted in its writeup. The points indicate the weight of that assignment relative to the others; i.e. an assignment graded out of 100 points has twice the weight of one graded out of 50.

Style is measured via several quality metrics (such as building cleanly, cleanly running under Valgrind, etc.) as well as a code review by the course staff. The style guide outlines further guidelines. Your style score is mapped to the following scale; from past experience, most grades will be ok.

  • + An outstanding job; reflects code that is notably clean, elegant and readable, and could be used as course example code for good style.
  • ok A good job; reflects code that demonstrates solid effort and is fairly successful at meeting expectations, but also has opportunities for improvement.
  • Has larger problems, but shows some effort and understanding. There were either large concerns, or a multitude of smaller concerns, in the submission.
  • – – Shows many significant issues and does not represent passing work.
  • 0 No work submitted, or barely any changes from the starter assignment.

Using these categories means that the course staff can focus on the assignment’s learning goals rather than spending time justifying each point. Our goal is to maximize the learning experience in doing the assignments, and we have found the "bucket" grading system to work much better for style feedback than assigning numeric grades from a pedagogical perspective over many quarters of experience.

Disputes about homework grading must be submitted to the course staff within 1 week of receiving your grade. For more information about the assignment grading process, please see our page on how assignments are graded.

Assignment Late Policy

Every student begins the quarter with five free "late days," to be used only for assignments (and not lecture check-in quizzes). Each late day allows you to submit an assignment up to one calendar day late without penalty. For example, if a due date is Wednesday at 11:59PM PT, using 1 late day allows you to submit until that Thursday at 11:59PM PT without penalty, and 2 late days allows you to submit until that Friday at 11:59PM PT without penalty. Late days may only be used in 24-hour increments. We will not accept assignments more than 2 days late and no late days may be used for the final assignment.

After the late days are exhausted, submissions that come in late will be assessed a late penalty per day late. Specifically, if you submit up to 1 day late, your score will be capped at 80% of possible points. This means that if you have a score above 80%, then your score will be lowered to 80%. If you have a score at or below 80%, your score will remain the same. Similarly, if you submit between 1 and 2 days late, your score will be capped at 60% of possible points.

You should think of free late days as extensions you have been granted ahead of time and use them when you might have otherwise tried to ask for an extension. As a result, getting an extension for exceptional circumstances beyond the provided free late days must be approved by the instructor. Only the instructor will be able to approve extensions. In particular, do not ask the CAs. All extension requests must be received in advance of the assignment deadline. Please do not hesitate to reach out to the course staff or the instructor if any personal circumstances or issues arise!


The midterm examination will be administered outside of class from 7:15-9:15PM PDT on Tuesday, October 26. If you have an academic or University conflict with this time, and absolutely cannot make the regularly scheduled midterm, you must send a request by email to the course staff by 11:59PM on Wednesday, October 20 to arrange an alternate exam time. Please include in your email all the possible times you are able to take the exam from Monday, October 25 to Wednesday, October 27. Any alternate midterm exam must be within this window.

The final examination is scheduled for Thursday, December 9th from 12:15-3:15PM PDT. There will be no alternate time for the final exam, except for those with relevant official university athletics or Office of Accessible Education accommodations. Please make sure that you can attend the final exam at the specified time before enrolling in the class.

All examinations are administered electronically and are closed-book; however, you will be allowed to bring in one double-sided 8.5x11" page of notes. A reference sheet will be provided to you during each exam, as well as beforehand for studying, containing commonly-needed information. No other materials may be used.

The Honor Code

Academic conduct for students at Stanford is governed by the Honor Code. Part of the Honor Code is a pledge and expectation to participate in class without seeking inappropriate help on graded work such as assignments and exams. Please read the separate Honor Code page; you are responsible for knowing all of the details at this link, and for following the Honor Code in this course. Violations of the Honor Code are taken very seriously; we reserve the right to use software tools to compare your submissions against those of all other current and past students, and will refer all suspected violations to the Office of Community Standards.

Course Resources


Required: Bryant & O’Hallaron. Computer Systems: A Programmer’s Perspective. 3rd Edition.

The bookstore has a less-expensive custom version of this textbook for our course that includes only the chapters we will cover; you can also use the regular full 3rd edition, which will come in handy if you plan to continue on to CS110 (which uses the rest of the book). You will need the 3rd edition of the textbook, which has substantial updates from IA32 to x86-64. There will be assigned readings from this textbook that are important preparation for lecture and lab. For readings that we assign, you can view a free digital PDF copy of the textbook on Canvas under the "Files" tab.

Strongly recommended: We also strongly recommend you have a "C language goto" in whatever form works best for you: textbook, tutorial, reference sheet, website, etc. As one suggestion, The C Programming Language by Kernighan and Ritchie is the classic text and a digital copy is available for checkout via Open Library (make a free account to "borrow" it digitally). Another option is Nick Parlante's Essential C reader PDF available here.

Our lecture readings pull from Bryant & O'Halloran, Kernighan & Ritchie, and Essential C.

Getting Help

We want to enable everyone to succeed in this course and offer several help resources. Read more about getting help in CS107.

  • Discussion Forum: The online discussion forum lets you search, ask and answer questions posted by fellow classmates. The course staff will also monitor and periodically respond to posts. The discussion forum is best for course policy questions, general course topic questions, or general assignment questions. It should not be used for specific questions about your assignment code.

  • Helper Hours: Helper hours are offered throughout the week, and are where you can sign up in a queue and get help from the course staff. Helper hours are best for course topic questions, general assignment questions, or questions about your code.

  • Course Staff Email: You can email the course staff at Please do not email course staff members individually. Emailing the course staff is best for private matters such as grade questions or personal accommodations. It should not be used to ask questions about course content or your assignment code.

  • Instructor Email / Helper Hours: For other sensitive or confidential topics, please feel free to email the instructor directly or stop by their helper hours to talk privately.

  • The course website houses various useful documents, such as how-to guides for the tools, and advice pages. Please take advantage of these resources!

Other Information

COVID-19 Precautions

In compliance with Santa Clara County policies effective August 2021, Stanford University is mandating the use of masks indoors for everyone, regardless of vaccination status. This means that whenever we spend time together indoors - in lecture, helper hours, labs and exams - we are each required to wear a mask. If we see someone not wearing a mask indoors, this is not necessarily a violation of the requirement. Some of us have health conditions precluding our ability to wear masks. Students in this situation should work with the Office of Accessible Education immediately, to receive an accommodation for a mask exemption. In addition, some of us might feel more comfortable wearing masks even when not required, such as when we are outdoors. Some of us might feel more comfortable social distancing even when not required, for example, during small-group work in lecture or lab and while masked. All of our preferences are reasonable, and it is important that we treat each others’ preferences with respect and care. You can find the most current policies on campus masking requirements on the COVID-19 Health Alerts site, and you can consult the Campus Safety COVID Checklist for guidance.

Planning for the Unexpected

While this course has been designed as a blended course, we may need to pivot to a fully online course in the event of a campus closure. If that happens, we will notify you of this change via email and the course website. Our lectures will then move to a fully online format, along with helper hours and labs. Exams will be administered online. We will do my best to support you through the transition to online learning. For additional information and updates, check out the Start Safe Stay Safe Website: Please be sure to sign up for emergency notifications from the University:

Affordability of Course Materials

All students should retain receipts for books and other course-related expenses, as these may be qualified educational expenses for tax purposes. If you are an undergraduate receiving financial aid, you may be eligible for additional financial aid for required books and course materials if these expenses exceed the aid amount in your award letter. For more information, review your award letter or visit the Student Budget website. (

SCPD Video Notice

Video cameras located in the back of the room will capture the instructor presentations in this course. For your convenience, you can access these recordings by logging into the course Canvas site. These recordings might be reused in other Stanford courses, viewed by other Stanford students, faculty, or staff, or used for other education and research purposes. Note that while the cameras are positioned with the intention of recording only the instructor, occasionally a part of your image or voice might be incidentally captured. If you have questions, please contact a member of the teaching team.