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Hobby x86 kernel written with Zig

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Re: Hobby x86 kernel written with Zig

#41

Post by bambataa »

jackhalford wrote: post #4

Hi, author here! I've just finished writing the pre-emptive multitasking [0](only round robbin though, nothing fancy). I'm currently writing an ATA driver [1], the idea is to implement ext2. I used to do this in Rust but I switched to zig for maintainability and readability over Rust. It seems that with `comptime` I'm able to make a lot of things optimal. Overall I have to say kernel programming is _hard_ but very re…

This looks really cool, well done. Do you mind sharing the resources you’ve used so far? I see many, many tutorials on OSDev...

Re: Hobby x86 kernel written with Zig

#42

Post by chungus_khan »

simias wrote: post #29
swiley wrote: post #15

Earlier quoted context omitted.

If you want more syntax weirdness: tab characters are illegal.

I don't mind opinionated coding style (my Rust integration scripts all enforce that stock "rust clippy" doesn't return any error) and I do think that using tabs for indentation simply doesn't work in practice regardless of how great they are in theory because hardly anybody uses them correctly (including the vast majority of code editors by default). It might be strange to back it straight into the compiler but I don…

> including the vast majority of code editors by default

Which ones exactly? Not really a problem I've encountered often except when someone tries to mix both spaces and tabs, and in general editors are built with the existence of this very common character in mind. People tend to hit the tab key to indent anyway, and one tab char meaning one level of indent is perfectly intuitive and allows users to individually configure how large they want their indents to be.

Re: Hobby x86 kernel written with Zig

#43

Post by pron »

rapsey wrote: post #38
jackhalford wrote: post #28

Earlier quoted context omitted.

In general you'll find that zig is easier to read than Rust (see the first version of this project in Rust [0]) because it's a simpler language. For kernel programming this is even more so the case: * zig has native support for arbitrary sized integers. In Rust I used to do bitshifts, Now I just have a packed struct of u3/u5/u7 whatever (see `src/pci/pci.zig`). Of course Rust has a bitflags crate but I didn't find it…

On the other hand safe Rust code will be memory safe..

It's Zig's goal to make it easy to write safe code, it's just that its approach to safety is very different from Rust's.

Re: Hobby x86 kernel written with Zig

#44

Post by pron »

simias wrote: post #9
guggle wrote: post #6

Earlier quoted context omitted.

> I used to do this in Rust but I switched to zig for maintainability and readability over Rust. Can you expand on this ? I'm asking out of curiosity because I want to learn a "system" programming language (for whatever definition there is to this term). So far I briefly tried Rust and Nim and found the former more difficult to read. I know nothing about Zig, how would you place it between these two ?

I'm curious too, I'm quite familiar with Rust and never written any Zig in my life so I went digging through the source and I find the syntax remarkably similar for the most part. The only thing that stood out is that apparently you can drop the braces for single-line `if` bodies like in C whereas Rust makes them always mandatory but I'm firmly on Rust's side on this one. The part where Rust can get really messy is w…

I wouldn't call Zig's comptime "C++-style." Unlike Rust, there's very little in Zig that is borrowed from C++. Zig's error reporting and comptime makes it easy to write arbitrary compile-time checks, so Zig uses a single construct and keyword, comptime, to replace all special instances of partial evaluation: generics, concepts/traits, value templates, macros and constexprs.

The main difference between Zig and Rust is a huge disparity in language complexity. Zig is a language that can be fully learned in a day or two. Rust has the same philosophy of "zero-cost abstraction" as C++, i.e. spending a lot of complexity budget to make a low-abstraction language appear as if it has high abstraction. Zig, like C, does not try to give the illusion of abstraction.

There is also the difference in their approach to safety, but that's a complicated subject that ultimately boils down to an empirical question -- which approach is safer? -- which we don't have the requisite data to answer.

Re: Hobby x86 kernel written with Zig

#45

Post by fortran77 »

jackhalford wrote: post #4

Hi, author here! I've just finished writing the pre-emptive multitasking [0](only round robbin though, nothing fancy). I'm currently writing an ATA driver [1], the idea is to implement ext2. I used to do this in Rust but I switched to zig for maintainability and readability over Rust. It seems that with `comptime` I'm able to make a lot of things optimal. Overall I have to say kernel programming is _hard_ but very re…

Zig is so much better than Rust for these sorts of tasks. Readable and maintainable. The Rust astroturf-brigade tries hard to make it fit any situation. I'm glad you have provided a substantial concrete counterexample.

Re: Hobby x86 kernel written with Zig

#46

Post by Touche »

alehander42 wrote: post #36
guggle wrote: post #30

Earlier quoted context omitted.

Thank you. > I don't know Nim, but I believe it has a garbage collector so it could be tricky to use for kernel programming. You're right. Still good for libraries though (or apps, but that may be outside of "system").

you're right, it is confusing, but it is optional: some toy kernels already work in nim , and with latest work on memory, you should be able to use most of the language for kernel development ! not the perfect language for that yet though, but i hope we should see more nim os examples

Are you saying that the GC is optional? If you don't use it how do you allocate/free memory?

Re: Hobby x86 kernel written with Zig

#47

Post by Touche »

joshbaptiste wrote: post #35
guggle wrote: post #30

Earlier quoted context omitted.

Thank you. > I don't know Nim, but I believe it has a garbage collector so it could be tricky to use for kernel programming. You're right. Still good for libraries though (or apps, but that may be outside of "system").

Nim's GC is optional

How can it be optional if there is lots of code that assumes you are using GC? For example, as far as I can tell the stdlib doesn't do its own allocations. Does this mean you can't use the stdlib with GC disabled? Or am I missing something here?

Re: Hobby x86 kernel written with Zig

#48

Post by woodrowbarlow »

rapsey wrote: post #38
jackhalford wrote: post #28

Earlier quoted context omitted.

In general you'll find that zig is easier to read than Rust (see the first version of this project in Rust [0]) because it's a simpler language. For kernel programming this is even more so the case: * zig has native support for arbitrary sized integers. In Rust I used to do bitshifts, Now I just have a packed struct of u3/u5/u7 whatever (see `src/pci/pci.zig`). Of course Rust has a bitflags crate but I didn't find it…

On the other hand safe Rust code will be memory safe..

not if you have to keep using unsafe blocks.

Re: Hobby x86 kernel written with Zig

#49

Post by jackhalford »

joshbaptiste wrote: post #40
jackhalford wrote: post #4

Hi, author here! I've just finished writing the pre-emptive multitasking [0](only round robbin though, nothing fancy). I'm currently writing an ATA driver [1], the idea is to implement ext2. I used to do this in Rust but I switched to zig for maintainability and readability over Rust. It seems that with `comptime` I'm able to make a lot of things optimal. Overall I have to say kernel programming is _hard_ but very re…

Author, if you decide to build more of this kernel any thoughts on providing live screencasts of the implementation like Andrew Kelly (Zig) and Andreas Kling (SerenityOS) on Youtube and/or Twitch. I never realized how effective it is for me to watch others go through the mental process of coding/debugging.

Hi, that's a great idea, it would be a good exercise for me especially. I always enjoy watching Andy's live zig coding on youtube.

Re: Hobby x86 kernel written with Zig

#50

Post by BubRoss »

swiley wrote: post #15
simias wrote: post #9

Earlier quoted context omitted.

I'm curious too, I'm quite familiar with Rust and never written any Zig in my life so I went digging through the source and I find the syntax remarkably similar for the most part. The only thing that stood out is that apparently you can drop the braces for single-line `if` bodies like in C whereas Rust makes them always mandatory but I'm firmly on Rust's side on this one. The part where Rust can get really messy is w…

If you want more syntax weirdness: tab characters are illegal.

Even weirder than that, it intentionally fails on \r\n newline, so windows text files straight up don't work by default.
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