CS 240: Introduction to Computer Systems (Spring 2021)

Basics of computer systems. Number representations, assembly/machine language, abstract models of processors (fetch/execute, memory hierarchy), processes/process control, simple memory management, file I/O and directories, network programming, usage of cloud services. 3 credit hours.

Prerequisites: CS 225

Course Staff

Course Meetings

All course meetings and office hours will occur via Zoom:

  • Course Meeting: Tuesday/Thursday, 12:30pm - 1:45pm
  • Office Hours: TBA

The CS 240 link to Zoom is provided to you via e-mail and is also in Compass 2g.

Course Assignments and Grades

Course grades are given in points, totaling 1,000 points throughout the semester. The breakdown of points is as follows:

  • Homework Assignments: 200 points (10 × 20 points), points over 200 are extra credit
  • Midterm Exam 1: 200 points
  • Midterm Exam 2: 200 points
  • Machine Projects (MPs): 250 points (10 weeks × 25 points)
  • Final Project: 100 points
  • Participation: 50 points

If less points are awarded (ex: if we have fewer than 10 homeworks), the sum of the points of the category will be scaled to the total number of assignment points. For example, if we have only 7 homeworks, 140 points will be scaled to 200 points (by multiplying it by 200/140) to ensure the relative weights between each category remain the same.

Final Course Grade

Course points will be translated into a course grade at the end of the semester.

Points Earned Minimum Grade Points Earned Minimum Grade Points Earned Minimum Grade
[1070, 1100] A+ [930, 1070) A [900, 930) A-
[870, 900) B+ [830, 870) B [800, 830) B-
[770, 800) C+ [730, 770) C [700, 730) C-
[670, 700) D+ [630, 670) D [600, 630) D-
[600, 0) F        

We might lower these cutoffs; for example, perhaps 670 points will turn out to be enough for a C-; however, we won’t raise them. (In recent courses I’ve taught these cutoffs have not moved significantly from these targets.)

Extra Credit

There will an opportunities for extra credit in this course (usually called “+1 points”). Points for extra credit work will be assigned after grade cutoffs are determined, so they are a true bonus to your score. The total amount of extra credit you can earn is capped at 100 points (though it’s unlikely we’ll have quite that many, but just in case).


One significant component to this course is the completion of the course project (100 points). You will have ~3 weeks to complete the project at the end of the semester. With the project, you will focus on building a complete cloud-based service that is uniquely your own. It’s my favorite part of the class and you’ll apply so much of what you learned in the course while finishing your project.

Late Submissions

No late submissions are accepted without prior arrangements.

Academic Integrity

Collaboration is about working together. Collaboration is not giving the direct answer to a friend or sharing the source code to an assignment. Collaboration requires you to make a serious attempt at every assignment and discuss your ideas and doubts with others so everyone gets more out of the discussion Your answers must be your own words and your code must be typed (not copied/pasted) by you.

Academic dishonesty is taken very seriously in CS 240 and all cases will be brought to the University, your college, and your department. You should understand how academic integrity applies specifically to CS 240: the sanctions for cheating on an assignment includes a loss of all points for the assignment, the loss of all extra credit in CS 240, and that the final course grade is lowered by one whole letter grade (100 points). A second incident, or any cheating on an exam, results in an automatic F in the course.

Academic integrity includes protecting your work. If you work ends up submitted by someone else, we have considered this a violation of academic integrity just as though you submitted someone else’s work.

Campus Resources

Mental Health

Diminished mental health, including significant stress, mood changes, excessive worry, substance/alcohol abuse, or problems with eating and/or sleeping can interfere with optimal academic performance, social development, and emotional wellbeing. The University of Illinois offers a variety of confidential services including individual and group counseling, crisis intervention, psychiatric services, and specialized screenings at no additional cost. If you or someone you know experiences any of the above mental health concerns, it is strongly encouraged to contact or visit any of the University’s resources provided below. Getting help is a smart and courageous thing to do – for yourself and for those who care about you.

Counseling Center: 217-333-3704, 610 East John Street Champaign, IL 61820

McKinley Health Center: 217-333-2700, 1109 South Lincoln Avenue, Urbana, Illinois 61801

To obtain disability-related academic adjustments and/or auxiliary aids, students with disabilities must contact the course instructor and the Disability Resources and Educational Services (DRES) as soon as possible. To contact DRES, you may visit 1207 S. Oak St., Champaign, call 217-333-4603, e-mail or go to If you are concerned you have a disability-related condition that is impacting your academic progress, there are academic screening appointments available that can help diagnosis a previously undiagnosed disability. You may access these by visiting the DRES website and selecting “Request an Academic Screening” at the bottom of the page.

Family Educational Rights and Privacy Act (FERPA)

Any student who has suppressed their directory information pursuant to Family Educational Rights and Privacy Act (FERPA) should self-identify to the instructor to ensure protection of the privacy of their attendance in this course. See for more information on FERPA.