os01 VS serenity

Write an OS from scratch

(Here is the link - didn't quite get the image/link combo right in the original post!). I'm writing a series of posts about coding your own operating system. After reading Operating Systems: From 0 to 1 I found that some of the code does not work, so this first post walks you through writing a bootloader similar to that of chapter 7. It also adds some context that I would have found useful when I originally read the book, such as how 16-bit real mode works and some assembly programming information. I'm hoping to take a different approach to posts in the series by borrowing pieces of other operating systems and discussing how they are implemented in an effort to keep things simple and focus on fundamentals (even Linus started out with a detailed reading of MINIX).

Starting a series about writing your own operating system. After reading Operating Systems: From 0 to 1 I found that some of the code does not work, so this first post walks you through writing a bootloader similar to that of chapter 7. I'm hoping to take a different approach to posts in the series by borrowing pieces of other operating systems (even Linus started out with a detailed reading of MINIX).

Very quickly skimming through the various chapters, it appears that this is gentle introduction as attention has been made on clear and verbose explanations, supplemented with diagrams. Comparable other "courses" could be osdev101 [1] and "Writing an operating system from scratch" [2].

[1] https://github.com/tuhdo/os01/blob/master/Operating_Systems_...

[2] https://www.cs.bham.ac.uk/~exr/lectures/opsys/10_11/lectures...

You need to be aware of how it works on a hardware level but probably not an expert, for a better explanation see: https://github.com/tuhdo/os01

Operating Systems from 0 to 1

SerenityOS replicates that look and feel. It is also implemented in a dialect of C++ that adheres to some of the good parts of C++98: https://serenityos.org

One example of a useful technique

https://serenityos.org/ apparently only makes source code available. There are no binary images of the OS to install

I think Andreas said this functions like a little test -- if you're not willing to build it from source, then you probably wouldn't be a good contributor anyway.

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Likewise, my shell project provides source tarballs only, right now - https://www.oilshell.org/release/0.21.0/

It is packaged in a number of places, which I appreciate. That means some other people are willing to do some work.

And they provide good feedback.

I would like it to be more widely available, but yeah I definitely see that you need to "gate" peanut gallery feedback a bit, because it takes up a lot of time.

Of course, it's a tricky balance, because you also want feedback from casual users, to make the project better.

Indeed, given the existence of `JS::NonnullGCPtr`, `JS::GcPtr` intentionally corresponds to a nullable pointer, so it seems dangerous to convert one to a reference without a null-check.

That said, a naive code search finds what *may* be more cases of this pattern:

https://github.com/search?q=repo%3ASerenityOS%2Fserenity+%2F...

Eg: https://github.com/SerenityOS/serenity/blob/a68b134e6dea5065... -> https://github.com/SerenityOS/serenity/blob/a68b134e6dea5065...

In some of those search results, it is fine because there is a preceding null-check, and obviously I know nothing about this code other than this naive search result, but perhaps it would be prudent to vet all of them.

It is a SerenityOS project. You can find the answer to that question in their primary project's FAQ[1].

1. https://github.com/SerenityOS/serenity/blob/master/Documenta...

https://github.com/SerenityOS/serenity

The best way to write proper exception free C++ is not to use the C++ Standard Library.

I initially confused it with Serenity OS prior to watching the video: https://github.com/SerenityOS/serenity

My contributions to SerenityOS[0] helped me get my current job. My team lead (who was also my interviewer) was interested in what I did since I listed some of it in my CV, and I showed him some PRs I made and explained what went into each of them. It was really exciting because I didn't have professional experience with low-level development, and basically got the job due to hobby programming.

[0]: https://github.com/SerenityOS/serenity/pulls?q=is%3Apr+autho...

Definitely not "literally impossible", just a great deal of work. https://github.com/SerenityOS/serenity/tree/master/Ladybird