hckrnws
Show HN: My from-scratch OS kernel that runs DOOM
by UnmappedStack
Hi there! I've been on-and-off working on TacOS for a few months, which follows some UNIX-derived concepts (exec/fork, unix-style VFS, etc) and is now able to run a port of Doom, with a fairly small amount of modifications, using my from-scratch libc. The performance is actually decent compared to what I expected. Very interested to hear your thoughts. Thank you!
A few months work by one guy and already more capable than the Hurd.
Imagine what you could accomplish given 35 years.
Haha not quite at the point Hurd has gotten. I'd be very happy if I could last that long on one project though, I have a tendency to get bored after a few months sadly.
> Haha not quite at the point Hurd has gotten
that's true, you've only shipped to one computer, while they've shipped to dozens!
From-scratch kernel straight to DOOM is some top-tier hacker cred stuff. You must be very happy with it running on real hardware. Very cool.
Really really love the name.
In the fine tradition of Nachos and Pintos! (Still waiting on Burritos - which would obviously have to be based on functional programming principles - and Churros.)
Burritos are just monoids in the category of endotacos.
welp I think I found my favorite comment ever.
Dude, getting Doom to run on your own kernel is epic - I gotta try building some wild stuff like this someday
Yeah definitely an achievement I'm happy with. I've got a bit of refactoring to do, ANSI parsing etc then I'd like to port more - perhaps even Vim (or another portable Vim-like editor called Dim)
Could you explain more about why you'd need to port things? If you have a libc, shouldn't it "just work"? Do you have to scatter #define or #ifdef all over? What about if you wanted to support Golang? Would you have to implement a bunch of syscall?
Well, the LibC is still quite small, and the syscalls aren't really compatible with Linux. A lot of things to port, for example Vim, require system libraries such as ncurses which need syscalls that aren't in the LibC. I don't really need many #ifdefs, at least not for most things, as it's a more or less posix-based libc.
Hi, congratulations! You must be feeling proud. Nice choice of proof of concept (DOOM).
Sorry to disappoint you but all I have are some noob questions.
What would be the steps to run this on a laptop? I take it that after building it there would be a process similar to, say, setting up dual-boot in a Windows PC? (Whoa I'm asking a stranger on the Internet how to run dangerous software on my computer...)
If one wanted to undertake such a project, do you have any recommendations of textbooks or other reading material? I had some OS & related courses in university (I'm EE, so computer-adjacent), but they were all very abstract / high level / conceptually-focused. I'd love something more concrete. It doesn't have to be x64.
Meta comment, but I'm pretty disappointed that this got downvoted so much. You're asking some good questions that prompted useful answers and showed sincere interest in someone's work. Don't get discouraged by the downvotes, keep learning!
Not being upvoted to the top doesn't mean downvoted, don't create a negative situation that doesn't exist.
Not disappointed at all to answer! Running it on my laptop was literally just formatting a USB with the ISO and booting from the USB.
I would recommend checking out https://osdev.wiki to start out if you want to write a kernel, as well as reading relevant specifications (such as Intel Developer Manual and the specs for any drivers you write). I don't really know much about non-x86 kernel dev but most of the concepts are the same as far as I know, just different technical implementations. There's a link to a discord server on the project's readme, there are some very smart people in there who I'm sure would be more than happy to help you out.
This is so cool
Dude, I'm impressed cause I don't the energy to build my own OS kernel!
But here's a wacky idea. Just set it up so that the OS only runs DOOM as default. Boots directly into Qemu and runs DOOM, nothing to select or change. Maybe something you could fold other games into so that they can run off a USB boot loader. Might be appealing to people who don't want to install or compromise their base setup.
I could probably do that. The init program, which is a userspace program called by the kernel which spawns everything else, currently enters the shell but it'd be quite simple to make it just boot into Doom immediately. It's still not quite stable enough for actual usage, but it is able to boot off a USB at the moment, yes.
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Crafted by Rajat
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