The tests are difficult but manageable. The labs/homeworks are pretty easy, especially if you attend discussion where the TAs went over the hard parts of each lab.

There is a lot of course content to be taught in one quarter, and to be honest, it felt like this class was made to be taught in a semester instead. Be prepared for a lot of reading.

The lectures are fine, and he teaches the course content pretty well. The labs are pretty easy, especially compared to previous versions of this course.

However, the exams are terrible. The wording of questions is so confusing and at times it feels more like an english or reading comprehension test than an actual test of operating systems. I know other people felt this way too -- after the midterm, people on Piazza primarily asked for clarification on the wording of questions. Despite how much you know or understand about the topic, if you're misunderstanding the wording of a question, you're not getting any points. Sometimes questions are kind of ambiguous and you just have to know the intention or mindset that Reiher was in when he wrote the question. The final was a little better than the midterm on this front, but both had the same issue.

Presentations are really organized. However, exam questions are worded poorly, and confusing to understand what it's asking for and what the correct answer is even if I had mastery of the material.

Probably one of the most underrated CS professors at UCLA. I really don't understand why people don't like him. Projects are trivial compared to other CS classes (looking at you, 35L), and never took more than a few hours. Tests were online, and while difficult the format made it pretty chill. Lecture and textbook readings go together nicely, and the content is extremely important and most of it I found interesting. I think this is the class where I REALLY learned how computers worked, which was pretty cool and kept me motivated. I think the haters just don't like how much information is covered in the class (feels a lot more like a hard GE than a critical thinking/problem solving type of class), which you can't blame the professor for (that's just how OS is). Overall, I would 100% take 111 with Reiher over anyone else.

Honest breakdown of Reiher: Overall, he's a pretty decent prof, the issue is that there is simply too much content for any reasonable human to fully comprehend in 10 weeks. There's probably about 80-100 pages of dense cs reading a week, which we will test you oddly specific concepts on. On top of this, each lecture feels like it's going at 1.5x bc there is so much content to cover. IMO most of the lecture content is pretty interesting, but the book goes into too many niche applications which isn't my interest, so I summarized them all with GPT.
Grade Breakdown:
1% Class Eval (Free)
9% Lab 0, 11% Each Lab
Labs have absolutely nothing to do with lecture, and are never tested on (as said by Reiher himself). They're sort of interesting to do, but if you value your time, I'd suggest finding them online. They're also graded super harshly, and small mistakes can be costly, so be sure to check it on a lot of cases.
20% MT, 26% Final
These tests are too hard for anyone to practically understand. Get a megadoc with all readings + lectures, and get ready to spam ctrl-F and/or find a good group. You can try to use GPT, but the questions are so hard and tricky that GPT scores consistently worse than the mean. The penalty is super harsh for tests, every wrongly selected answer is negative points, and selecting multiple or choose between options is very very hard. If this test was in person and not open note, I'd say the average would be below 30%. There is too much information to study for anyone.

Advice: Lectures are interesting and good for high-level understanding. Summarize readings unless you want to spend 5-7 hours a week making super detailed notes. Find a good group. This class isn't great, but isn't terrible if you work smart.

Interesting class. Lots of readings and material, but you learn a lot. My only complaint is that the tests were terrible. I felt like the answer choices were way too broad/unclear I would actually prefer in person exams to whatever we had on Canvas.

REIHER SUPPORTS CHEATING! TAKE EGGERT INSTEAD PLEASE!

Professor Reiher is lazy and writes horrible exams that are NOT curved. He rewards students who cheat and makes the lives of students who genuinely care about maintaining integrity and honestly really hard. He turns a blind eye on all exams and assessments and leaves them open and unproctored. The grading is what it is. There are many ways to interpret The assessments and grading are NOT a good reflection at all of how well you understand Operating Systems. For context, his midterm (20%) and final (26%) are entirely multiple choice questions done at any time in a 24-hour window (timed once you start).

Worst of all is the grading. Reiher minimizes his own workload by letting BruinLearn handle the point system which is ATROCIOUS. Because most of his MCQs are "Select All That Apply" and say you picked 2/3 correct options and only selected one wrong. Sounds like you understand most of it, right? NO! YOU GET 3/10 POINTS ON THAT QUESTION. And this sucks because there are so many edge cases and apply to circumstances that you COULD argue one way or another. I hate his philosophy on this and seems like a way to avoid doing any work as a professor for grading.

Students are ACTIVELY cheating on his exams because it is so open and unproctored. Cheaters could just work with other students secretly, or use AI, or get all the questions ahead of time from earlier test takers. I suffered greatly from this because I cared and Reiher didn't. The most fair students receive the worst grades, and all the cheaters receive the best ones.

You DON'T get a chance to explain yourself or how you interpreted the wording of the question.

The saving grace of this class is that everything can be done remotely (everything is recorded and posted, textbook is free and online, labs (53%) are easy and generally graded okay).

ONE OF THE WORST COURSES I'VE TAKEN AT UCLA.

The lecture and the lecturer is interesting. The content is clearly delivered and presented. The textbook is easy to read and useful. The exam is hard, but everyone suffers.

However, the grade that the professor gives out is not good. Only 25/160 gets an A in my quarter (basically, the professor does not curve up the grade. He only gives raw score, and the mean/median of midterm is around 75-77, and final is about 77-78).

In general, I find the textbook to be very good. However, the Professor's slides and writings are often confusing. Sometimes, contradicting information can be presented in the same slide with very confusing wordings.

Professor Reiher is great at making a very structured course on this large topic and explaining the content well. The problem is that there is too much content. I maybe understood some things but I will leave this class not really fully appreciating the different aspects of it. I know it is an introduction class, but I would trim it down more and maybe split it into how CS31 and CS32 is split. This will greatly benefit everyone.