https://pdos.csail.mit.edu/6.S081/2021/xv6/book-riscv-rev2.p...
So far, it is saying all the things that need to be said once, once, and very clearly.
I still chuckle at another student's description of the class... "a crash course in enabling and disabling interrupts in order to prevent segfaults and pagefaults.
I came across a compiler bug when doing the course with gcc outputting incorrect ASM which was quite exciting as I've never come across one in the wild before. I really should check if that's been fixed and report it if not.
One of the requests on the course was to include time taken for the assignments as part of the submission. This was part of the (locally run) grading script, so even though I didn't submit I still completed it, luckily.
There were 11 assignments, and each took 5-10 hours apart from a few I got stuck on - I've got one assignment listed as being 30 hours (and I still remember the frustration. I nearly got to the point of emailing the course creators to ask for help but figured it out in the end as part of it was my aforementioned compiler bug).
On top of this there are two lectures a week (often ran over time with questions) so about 3 hours per assignment and some reading material.
I had used C before this course and was very rusty. This caused me to make some mistakes in the beginning, like pulling in standard libraries rather than using the ones as part of XV6, that someone new to C would likely not have made.
So in total I'd say 36 hours of lectures, 10 hours reading, 100+ hours doing assignments.
when i took operating systems, we extended linux with an eye to building reliable systems (we built stuff like fault injectors for syscalls) as that was where the professor's graduate work had been and made various toy modifications to actual linux subsystems.
maybe folks working with nachos or one of these other toy operating systems get more topical depth (implement a scheduler or vm subsystem from scratch or such), but i personally found the experience of making real modifications to linux to be both more interesting and rewarding. (although many in the course struggled)
if you're aiming to be an embedded person someday on things like scada and such, or are interested in reverse engineering old hardware and systems and care a lot about device interfaces, them maybe one of these operating system as library frameworks would be a better choice.
depends what your goals are i guess.
https://news.mit.edu/2021/mit-put-unexpected-gains-work-imme...
Every R1's endowment pays for everything a school must do: campus shuttles, sending lab kits to remote students during a lockdown, funding research activities (conferences, equipment, student salaries, journal fees), supporting student clubs, building/maintaining modern facilities, allowing poorer students---those already overcoming disadvantages relative to their peers---to focus on studying instead of working, poaching leading instructors from around the globe, building reactors.
According to https://ocw.aprende.org/donate/why-donate/ (a slightly older mirror of OCW's current donate page) MIT gets half of its $3.5 million budget from the institute while the remainder comes from donors. I also don't know that MIT is allowed to dip into the OCW fund for planting trees and endowing professors, so a donation probably actually goes toward maintaining AV gear, paying undergraduates to write captions, ensuring legal compliance, paying external courseware developers and Github fees.
(Yes, they occasionally hire external writers. I did this one summer before private repositories were free. OCW hires also get MIT certificates, which unlock a lot more course materials on MIT domains if you search a bit.)
At 2 million visits per month, one percent of visitors giving 5 dollars each year falls short of their budget by 500 grand. Do you think even one percent gives? Do you think they had 2 million site visits last month?
I don't know if they monetize their Youtube channel either. I can't recall ever seeing ads on their videos.
Ultimately, a lot of people are leeching off of large donors and corporate sponsors, who get back---at least short-term---practically nothing for their support. I see the school's perspective, why give more if users (or benefactors) are unwilling to support a reasonably worthy cause?
(If you need proof that a leading university will revoke its charitable publishing of course materials, look no further than UC Berkeley, which took the ball home after being ordered to add closed captions to free lecture videos.)
In short, I would recommend giving a few coffees worth to OCW before giving to Wikipedia (for the same reason you'd pay for universal grade school whether you have children or not), and I have historically done both.
(Shrug) Neither does God, so I guess it's up to you and sydthrowaway what you do with your $5.
I guess some of the GUI stuff is worth something, but you can just make a ray traced OS with Unity so.
