Show HN: A DOS-like hobby OS written in Rust and x86 assembly

by krustowski • 1 year ago

207 60 1 year ago

To try it out, simply build the project yourself from source, or use attached bootable ISO image of the system (in Releases on Github) and run it in QEMU.

https://blog.vxn.dev/rou2exos-rusted-edition

rollcat2• 1 year ago

Memory-safe language. x86_64, with Arm on the roadmap. Networking stack. Boots from a CD and via multiboot. Your hobby project wipes the floor with DOS.

pvg• 1 year ago

Whoa there. Gotta run Doom and BASIC to compete with DOS. That is the officially recognized DOS-Kármán line.

krustowski12• 1 year ago

What a challenge! Need to implement some interrupts it seems then, to provide an API for filesystem and so... Thank you for such idea

rollcat2• 1 year ago

DOOM required DOS 5.0. rou2exOS is only the second take. Watch this area ;)

jdsully• 1 year ago

Nobody cares about Lotus 1-2-3 support any longer :)

mycall• 1 year ago

also, can't be a dos with the 'dir' command.

pjmlp2• 1 year ago

Borland languages and xBase ecosystem as well

MoonGhost• 1 year ago

Rust and x86 assembly

then

Memory-safe language.

What's the point? Looks like today Rust is like 3D printing was. As if it makes something better. Printing was hyped and advertised by printers sellers and manufacturers. Finally they run out of money.

As for project, it's cool if compatible with old soft. Otherwise suitable mostly for education and masochism. Long way to become practical anyway even if it gets traction.

unchar1• 1 year ago

You can write memory safe code in any language, but having a machine i.e. the Rust compiler check it for you is less error-prone than if a human does it.

Also if you look at the repo, only 3% of the codebase is in Assembly. IMO if >95% project is in Rust, you can definitely claim it's a Rust project.

whytevuhuni• 1 year ago

The idea of Rust is not that it is 100% safe, but rather that it is able to encapsulate unsafety and divide the program in two parts:

- unsafe code plus modules that support it (the "trusted base")

- all the rest

Rust's promise is that there is no way to trigger any undefined behavior from bugs happening in "all the rest" of the code. If that code makes for more than 95% of the total, then that's a huge win compared to a completely unsafe language.

Also, Rust's support for inline assembly is in my opinion better than C's, it's much easier to specify and figure out the constraints on the boundary between Rust/assembly.

krustowski12• 1 year ago

Well, the point is to experiment with Rust no_std+no_main environment while trying to educate myself on how the things work under the hood. The project itself is part "just" a rewritten system (from C to Rust), and part an enhancement of such system furthermore. It lacks the external program execution though yet.

DrNosferatu2• 1 year ago

DOS-like but not DOS-compatible, correct?

krustowski12• 1 year ago

You are right. The first iteration however is 16bit and is very close to MS-DOS in terms of compatibility. Moreover, any OS that can handle simple disk I/O ops could be considered a DOS system too, innit?

leeter2• 1 year ago

Correct, there is a difference between MS-DOS and IBM-PC compatible and a DOS (ex: all the DOSes that existed for Amiga/Apple II/Commodore etc). There are many DOSes (and even MSDOSes, because yay early PC era incompatibilities!), but there is a very dubious list of things needed to be MS-DOS and IBM-PC compatible. You can probably do it if you're willing to setup a hypervisor and emulate some hardware.

NGL one of my long term projects was/is something exactly like this but UEFI and secure boot. The idea being to use the VM extensions to create IBM-PC and DOS compatible environments. For anything using DPMI[1] I'd probably do the same trick as Win95 did and just replace it with my own implementation so it's not too overburdened with layers.

[1] https://en.wikipedia.org/wiki/DOS_Protected_Mode_Interface

snvzz• 1 year ago

The 16bit one also looks fun[0] and would run on old PCs the new one does not. Have you considered open sourcing that one?

0. https://krusty.space/projects/rourexos/

DrNosferatu2• 1 year ago

...meaning MS-DOS compatible :)

I.e.: runs Alley Cat and Dune 2 - and Doom.

JdeBP2• 1 year ago

And prevents Lotus 1-2-3 from running? (-:

mixmastamyk2• 1 year ago

I would have preferred something like this to the current UEFI environment and shell, a FLOSS 64-bit DOS-like. A cool retro boot manager and diagnostic env perhaps.

Could this run from an efi system partition? Seems to support fat12, what about gpt?

Does it poke video hardware like DOS, or have a terminal like output?

krustowski12• 1 year ago

Booting from an EFI system partition has not been tested yet. FAT12 is the only filesystem (ok, there is a memdisk implementation, but it won't work now) supported, so GPT is not supported at the moment too (yet). Kinda aiming for FAT32 implementation to be the very next implemented (flash disks are usually FAT32 iirc). Not sure about the last question: the OS utilizes/directly writes to the VGA buffer in memory, the provided resolution is 80x25 by GRUB.

mixmastamyk2• 1 year ago

So MBR partitions? Or no partitions, like from a floppy? Or perhaps it doesn’t know because grub handles that part.

OhNotAPaper• 1 year ago

Out of curiosity, why x86? Is it the preponderance of resources? The weird instruction format? The complexity of the boot sequence? Are you specifically trying to mimic DOS?

A support for the ARM architecture (aarch) is coming soon too.

Wow! How do you support a DOS-like OS across multiple architectures when DOS itself is tightly tied to interactions among the program, the system code, and the architecture?

anyfoo2• 1 year ago

I have not looked at this project, but my guess would be: x86 is a widely available platform that, because of its history and relentless compatibility, contains a lot of legacy interfaces that make implement a very simple, thin-layer and “DOS-like OS” without the need to parse device trees, set up MMUs, deal with complex busses like PCI(e) and so on.

It is much harder to bootstrap a simple OS in ARM, and it won’t stay very simple unless you accept significantly more limitations than you would under x86. (For example, you can’t do very much with the MMU off on ARM, and you also don’t have convenient BIOS interfaces that allow you to, say, read a sector, or wait for a keypress, with just a few lines of assembly).

krustowski12• 1 year ago

The x86 arch is used because this system iteration derives from the first one, which relies on BIOS interrupts and inline assembly in Turbo C. I am not trying to mimic (MS-)DOS exclusively, but both systems are highly inspired by it.

IMO multiple archs could be supported as Rust compiler allows the target arch specification, so one would build a specific target before the build itself.

mct• 1 year ago

I love that the networking stack uses SLIP and slattach(1)!

I was playing with a toy TCP/IP stack, and decided using SLIP over a pty on Linux was a great way to interface with the kernel. Unfortunately it looks like macOS previously shipped with slattach(1) a very long time ago, but no longer does.

I'm curios if other people have used SLIP on macOS to get a dead-simple, cross-platform API to the networking stack?

The alternative would be to use tun/tap on Linux and utun on macOS, but SLIP would be so much nicer.

jmmv2• 1 year ago

I don’t understand: what makes this “DOS-like”? Not even the command names match DOS, except for dir and cls, and the architecture and feature set are completely different.

paulannesley• 1 year ago

Single-user, single-task, VGA text-mode operating system with a basic filesystem (fat12), I guess.

Note the “guest” username in the prompt is a const, not multi-user: https://github.com/krustowski/rou2exOS/blob/6f85955dd339f09d...

klank• 1 year ago

The original blog post has more details: https://krusty.space/projects/rourexos/

Ultimately, it's an eye of the beholder type thing, but it seems very fair to call it DOS-like to me. The DOS inspiration is pretty blatant all throughout it from its aesthetic, commands (more than just dir and cls is shared), booting from a 1.44 floppy, etc. And if you are coming from a primarily windows computing background, then "DOS-like" is entirely appropriate to me.

It looks like a fun project.

jmmv2• 1 year ago

Ah yes, the first version does indeed sound DOS-like. The second one diverges quite a bit though.

Fun project indeed.

90s_dev2• 1 year ago

Is this using a custom VGA driver from scratch in Rust??

90s_dev2• 1 year ago

src https://github.com/krustowski/rou2exOS/tree/master/src/vga

krustowski12• 1 year ago

Sort of, but IMO that module(s) is just a wrapper for video buffer.

m00dy• 1 year ago

it needs event queue to support async runtimes.

krustowski12• 1 year ago

How about the event loop in its completeness?

pndy• 1 year ago

Are you planning adding support for Czech diacritics?

krustowski12• 1 year ago

I am not at the moment. The goal is to keep this iteration in English for now. The first iteration was in Czech in the beginning though.

Toritori12• 1 year ago

Good job OP, what a missed opportunity to say: "just a hobby, won't be big and professional like Linux" (:

ta12653421• 1 year ago

Can it run Crysis??

:-))

Show HN: A DOS-like hobby OS written in Rust and x86 assembly

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