[shetaye]

People interested in a "read the manual and code it up on real hardware"-type guide should take a look at Stanford's CS140E[1] repo! Students write a bare metal OS for a Raspberry Pi Zero W (ARMv6) in a series of labs, and we open source each year's code.

Disclaimer: I'm on the teaching team

[1]https://github.com/dddrrreee/cs140e-25win

[firesteelrain]

Do you have the course online? Looks like a bunch of files

[shetaye]

There aren't any 1hr+ lectures, just some readings (selected from the manuals in `docs/`) and a bit of exposition from the professor before diving into the lab. Lots of "as needed" assistance

[firesteelrain]

Interesting. Now I am wondering if I could build an OS for the Zero. I have five of them sitting in my drawer

[shetaye]

You absolutely can, and should! :)

[zeroq]

not really my cup of tea, but a random feedback: take a look at nand2tetris as it's really "user friendly" and, if I'm not mistaken, was even made into a game on Steam.

[kragen]

It is user friendly, and it's astounding how much they managed to pack into a single semester. Highly recommended!

However, it's arguably too idealized and predetermined. I think you could get all the way through building the computer in https://nandgame.com/ without really learning anything beyond basic logic design as puzzle solving, but computer organization, as they call it in EE classes, is more about designing the puzzles than solving them. Even there, most of what you learn is sort of wrong.

I haven't worked through the software part, but it looks like it suffers from the same kind of problems. IIRC there's nothing about virtual memory, filesystems, race conditions, deadly embraces, interprocess communication, scheduling, or security.

It's great but it's maybe kind of an appetizer.

[shetaye]

IMO this is kind of the tradeoff. In 140E we do touch on virtual memory (w/ coherency handling on our specific ARM core), FAT32 "from scratch", etc. but it comes at the expense of prerequisites. There is a lot of effort to "minify" the labs to their core lesson, but there is an inevitable amount of complexity that can't (or shouldn't) be erased.