Oh hey, we've reached the "Metal" stage! https://www.destroyallsoftware.com/talks/the-birth-and-death...
Love this. An example of complete and total dominion over the machine. Great quote here too lol
> Prometheus stole fire from the gods and gave it to man. For this he was chained to a rock and tortured for eternity.
The choice of Duktape here is smart — it's one of the few JS engines that can actually run freestanding with minimal libc stubs, since it was designed for embedding in constrained environments. V8 or SpiderMonkey would be a nightmare to get running pre-boot.
What I find most interesting is the UEFI services binding approach. Rather than trying to abstract away the hardware, it exposes the raw EFI protocols (GraphicsOutput, SimpleFileSystem, etc.) directly to JS. That's a much more pragmatic design than trying to build a full HAL — you get to prototype UEFI applications rapidly while keeping the escape hatch to C for anything performance-critical.
Would love to see if anyone tries hooking this into UEFI's built-in network stack for PXE boot scripting. That could actually be useful beyond the novelty factor.
Are em-dashes really that common to use or did I just start noticing them after LLMs became popular for rewriting comments?
Not implying your comment is LLM generated, clearly it isn't but asking as a genuine question.
Can someone break this down for me? Looks like it's using... C? to load a js interpreter which bootstraps an API around all UEFI features? Do I have that right?
And, if so, does that mean that once the API has been bootstrapped, one could actually write an OS in js? Or are there other abstractions that would need to be migrated first?
You don't need a JS bootloader to write an OS in JS. The bootloader just drops the machine into some memory address for it to start executing your OS init script. that bit could be a Javascript interpreter. You can't do much with the architecture in Javascript though, because it doesn't allow you to map memory directly to your types (unless there's some ungodly nonesense I'm not aware of) so you'll have to drop into C/asm to e.g. interact with the ports/registers/tables to set up userspace.
An OS doesn't need to have a user space :)
I'm pretty sure someone already compiled Linux to asm.js a few years ago. As asm.js is/was a subset of JS, you could say it's already been done. In theory, you could continue work from there in JS.
https://medium.com/@retrage/lkl-js-running-linux-kernel-on-j...
> And, if so, does that mean that once the API has been bootstrapped, one could actually write an OS in js?
I bet somebody has done that.
https://www.google.com/search?q=os+kernel+in+javascript
Seems like a small number of hobbyists have attempted.
I've heard of people doing this with other high level languages. Basically you need enough low level code to bootstrap a VM. Once you have that, you can make the high level language decide some logic that traditionally would be in C code, like manipulating page tables or whatever.
Automatic Garbage Collection in a kernel probably won't work:
I vaguely remember hearing about someone trying to use .Net in the Windows kernel.
The big problem is garbage collection: If I remember correctly, the fact that "any" operation can fail with an out of memory exception was a huge problem. Another problem was that random pauses for garbage collections in the kernel had major stability issues.
In short, I hope that the js kernel is for amusement and education; otherwise it would need a much more advanced garbage collector then earl 2000's .Net.
You'd need to write an entire hardware abstraction layer to do anything useful. There's projects that do this for microcontrollers - eg MicroPython and Espruino.
Depending on your definition of OS, yeah you could do that :)
Hey, when Apple transitioned from m68k to PowerPC, it took them a hell of a long time to rewrite massive parts of their OS. It's a low bar, though...
OS in JS, ok I am interested now...
I presume you'll add the network stack next, so that I can use my favourite, most useful packages?
import isOdd from "https://unpkg.com/is-odd";Well, there's a network stack already there, including HTTP and HTTPS on newer firmwares.
We are getting isOdd in the bootloader before GTA-IV
Wait, when did I time-travel?
oops typo
I think there are two philosophies here:
1) JavaScript must stay in the box (aka in the browser).
2) JavaScript as a general purpose programming language.
While I can absolutely understand 1), I have had wanted to access the filesystem via JavaScript, just as I do via ruby or python, for local use only. After I googled for a while, they would say that this is not possible unless one uses npm/node. I think this shows that there are use cases here and the "default" JavaScript, aka 1), does not cover these. I do not like JavaScript, but based on my own use cases, I actually favour 2) far more than 1). So from that point of view, being able to access UEFI can also be useful. So why not.
> I have had wanted to access the filesystem via JavaScript, just as I do via ruby or python
There are some (limited) ways to do so now: https://developer.mozilla.org/en-US/docs/Web/API/File_System...
As for (1) vs (2), it’s not really an issue of JavaScript at all. The main question is, do you want to build something that runs in a browser? If you’re building a web app, you’ll have to use the sandboxed APIs (and probably JavaScript). If you don’t care about the runtime, yeah, you can use Node or Bun or Deno (or use another language altogether).
Try webkitdirectory file attribute for browser access to the file system.
> If this makes you grin, you are probably holding the torch.
What if it makes me recoil in horror? screams into the void
This project will go places. Like every silly project not intended for production. :)
next step is to create a UEFI TUI using react (please don't)
you may just have casted a curse on our future motherboards, damn you
OMG we can use ink for that
This is hilarious lol, it’ll be any day now before we get a full JS kernel. Garbage collection could be an obstacle, but I know there have been some kernels written in Go/Java before
It could be even better!
Who needs to garbage collect? Just leak memory until the system dies! That strategy seems to be good enough for claude code, anyway.
If it’s good enough for missile guidance systems, it’s good enough for me.
Wow, this is cursed.
I think the proper term is blursed.
I think r/unixporn will love it once it gets DOM support :^)
Finally, we can create splash screen animations in pure CSS!
Does it manage to support floats? I am not sure if those can be safely used in the UEFI environment. (I recall GRUB’s build of Lua being integer-only, and Linux avoiding the use of floating-point arithmetic in kernel mode, but I don’t remember the reason.)
Yeah floats works
This is both so impressive and cursed that I'm not sure how to feel.
"The Birth and Death of JavaScript" is coming true after all.
I was going to post this as well! A direct link to the video: https://www.destroyallsoftware.com/talks/the-birth-and-death...
Could this be used as a learning tool? Rebooting the computer takes so much more time compared to reloading the browser tab. And you probably can't brick your computer.
I’m always amazed and slightly envious of what programming languages with large developer bases can do. I mean if a language is Turing complete it can do anything, but JavaScript takes this to the extreme.
Mind you I never said anything about quality or performance, obviously doing everything in JavaScript comes with it’s own issues but if you were to say that someone got JavaScript running in the Linux kernel as a POC I wouldn’t even be surprised
Turning in the widening gyre, the falcon cannot hear the falconer. The center cannot hold.. The old prophecy is coming true.
Awesome! Everything will be rewritten in JS
Can't wait for browser support for this... ;-)
webuefi has already been shipped by google for use on chromebooks. but mozilla and apple irrationally refuse to implement the standard for "security reasons"
Soon™
Yeah, but your [developers] were so preoccupied with whether or not they could, they didn't stop to think if they should.
This is incredible.
> If this makes you grin you are probably holding a torch
Hilarious
"Your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Pretty neat, though.
It begins!
Finally!
I love it.
But why?
It's just a silly experiment; the real endgame is to make a bootloader that is customisable using HTML/CSS/JS
Since PDFs can contain JS, presumably that should be the preferred way of modifying your boot loader.
Yeah that's the natural next step, I'll work on that next
Why not?
Because this can end very badly. It is a new surface to attack
Exactly! It's actually great! More ways to jailbreak stuff.
Why is it a new surface? Either you can run UEFI code, or you can't. Attacking the JS interpreter itself is unrealistic IMHO, it's the poorly written JavaScript running on top of this that might open new surfaces of attack. But other UEFI code is mostly written in C or C++, so let's call that a wash?
Maybe? What's your threat model?
Your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should!
Cursed
Whoa, I haven not been following ASM.js stuff in any detail.
Seeing that Metal replaces kernel/userspace boundaries with VM protections for memory, meaning that system call overhead is eliminated, at the price of ASM/VM overhead.
What a fascinating idea. Kidding on the square...
I'm doing my part ∠(‘-‘)
thank u 4 ur serves
Thank you for the reminder to do my yearly viewing of that video lol