alt.hn

3/9/2026 at 4:43:39 PM

JSLinux Now Supports x86_64

 https://bellard.org/jslinux/

by TechTechTech

3/10/2026 at 12:21:26 AM

Out of interest I tried running my Primes benchmark [1] on both the x86_64 Alpine and the riscv64 Buildroot, both in Chrome on M1 Mac Mini. Both are 2nd run so that all needed code is already cached locally.

x86_64:

    localhost:~# time gcc -O primes.c -o primes
    real    0m 3.18s
    user    0m 1.30s
    sys     0m 1.47s
    localhost:~# time ./primes
    Starting run
    3713160 primes found in 456995 ms
    245 bytes of code in countPrimes()
    real    7m 37.97s
    user    7m 36.98s
    sys     0m 0.00s
    localhost:~# uname -a
    Linux localhost 6.19.3 #17 PREEMPT_DYNAMIC Mon Mar  9 17:12:35 CET 2026 x86_64 Linux
riscv64:

    [root@localhost ~]# time gcc -O primes.c -o primes
    real    0m 2.08s
    user    0m 1.13s
    sys     0m 0.93s
    [root@localhost ~]# time ./primes
    Starting run
    3713160 primes found in 180893 ms
    216 bytes of code in countPrimes()
    real    3m 0.90s
    user    3m 0.89s
    sys     0m 0.00s
    [root@localhost ~]# uname -a
    Linux localhost 4.15.0-00049-ga3b1e7a-dirty #11 Thu Nov 8 20:30:26 CET 2018 riscv64 GNU/Linux
Conclusion: as seen also in QEMU (also started by Bellard!), RISC-V is a *lot* easier to emulate than x86. If you're building code specifically to run in emulation, use RISC-V: builds faster, smaller code, runs faster.

[1] http://hoult..rg/primes.txt

by brucehoult

3/9/2026 at 7:27:22 PM

The thing I most want to use this (or some other WASM Linux engine) for is running a coding agent against a virtual operating system directly in my browser.

Claude Code / Codex CLI / etc are all great because they know how to drive Bash and other Linux tools.

The browser is probably the best sandbox we have. Being able to run an agent loop against a WebAssembly Linux would be a very cool trick.

I had a play with v86 a few months ago but didn't quite get to the point where I hooked up the agent to it - here's my WIP: https://tools.simonwillison.net/v86 - it has a text input you can use to send commands to the Linux machine, which is pretty much what you'd need to wire in an agent too.

In that demo try running "cat test.lua" and then "lua test.lua".

by simonw

3/10/2026 at 12:09:29 AM

While this may be a better sandbox, actually having a separate computer dedicated to the task seems like a better solution still and you will get better performance.

Besides, prompt injection or simpler exploits should be addressed first than making a virtual computer in a browser and if you are simulating a whole computer you have a huge performance hit as another trade off.

On the other hand using the browser sandbox that also offers a UI / UX that the foundation models have in their apps would ease their own development time and be an easy win for them.

by zitterbewegung

3/9/2026 at 8:42:36 PM

> The thing I most want to use this (or some other WASM Linux engine) for is running a coding agent against a virtual operating system directly in my browser.

That exists: https://github.com/container2wasm/container2wasm

Unfortunately I found the performance to be enough of an issue that I did not look much further into it.

by the_mitsuhiko

3/9/2026 at 8:24:02 PM

Simon, this HN post didn't need to be about Gen AI.

This thing is really inescapable those days.

by jraph

3/9/2026 at 8:28:46 PM

Parallel thread: https://news.ycombinator.com/item?id=47311484#47312829 - "I've always been fascinated by this, but I have never known what it would be useful for."

I should have replied there instead, my mistake.

by simonw

3/9/2026 at 11:03:39 PM

I don't know man, I didn't see anyone say "this post didn't need to be about <random topic>", HN has just become allergic to LLMs lately.

I'm excited about them and I think discussion on how to combine two exciting technologies are exactly what I'd like to see here.

by stavros

3/9/2026 at 11:38:19 PM

You haven't been around here in the Blockchain/NFT/Smart Contract dark ages, have you?

by purerandomness

3/9/2026 at 11:39:17 PM

Naw man I just signed up.

by stavros

3/9/2026 at 11:59:11 PM

I chuckled. Everything on earth is recent if you look at it from a cosmic timeframe I guess

by yokoprime

3/10/2026 at 12:10:42 AM

To be fair, it really was annoying when everything was blockchain.

by stavros

3/9/2026 at 11:33:13 PM

Has there ever been any other topic that was not only the subject of the majority of submissions, but also had a subset of users repeatedly butting into completely unrelated discussions to go "b-but what about <thing>? we need to talk about <thing> here too! how can I relate this to <thing>? look at my <thing> product!"?

You can't just roll in to a random post to tell people about your revolutionary new AI agent for the 50th time this week and expect them not to be at least mildly annoyed.

by bakugo

3/9/2026 at 11:34:45 PM

I'm with you, but he wasn't telling us about his agent, he was saying "this is a cool technology and I've been wanting to use it to make a thing". The thing just happened to be LLM-adjacent.

by stavros

3/9/2026 at 11:50:53 PM

Almost all of his comments "just happen" to be LLM-adjacent. At some point it stops "just happening" and it becomes clear that certain people (or their AI bots) are frequenting discussion spaces for the sole purpose of seeking out opportunities to bring up AI and self-promote.

by bakugo

3/10/2026 at 12:17:02 AM

You are not reading his material i suppose? It’s really one of the better sources for informed takes on llms

by yokoprime

3/9/2026 at 11:52:23 PM

Simon has been here since way before LLMs were a thing, and it's fairly obvious (to me, at least) that he's genuinely excited about LLMs, he's not just spamming sales or anything.

by stavros

3/9/2026 at 10:38:35 PM

[dead]

by darig

3/9/2026 at 11:56:49 PM

What topics are allowed in your opinion? I very much enjoyed Simon’s comment as it is a use case I also was thinking of.

by yokoprime

3/9/2026 at 11:57:49 PM

a bit cute that you interacted with the 1 AI thread. there are other threads!

by grimgrin

3/9/2026 at 8:53:24 PM

Check out Jeff Lindsay's Apptron (https://github.com/tractordev/apptron), comes very close to this, and is some great tech all on its own.

by d_philla

3/9/2026 at 9:31:11 PM

It's getting there. Among other things, it's probably the quickest way to author a Linux environment to embed on the web: https://www.youtube.com/watch?v=aGOHvWArOOE

Apptron uses v86 because its fast. Would love it for somebody to add 64-bit support to v86. However, Apptron is not tied to v86. We could add Bochs like c2w or even JSLinux for 64-bit, I just don't think it will be fast enough to be useful for most.

Apptron is built on Wanix, which is sort of like a Plan9-inspired ... micro hypervisor? Looking forward to a future where it ties different environments/OS's together. https://www.youtube.com/watch?v=kGBeT8lwbo0

by progrium

3/9/2026 at 10:37:44 PM

This is not the technical solution you want, but I think it provides the result that you want: https://github.com/devcontainers

tldr; devcontainers let you completely containerize your development environment. You can run them on Linux natively, or you can run them on rented computers (there are some providers, such as GitHub Codespaces) or you can also run them in a VM (which is what you will be stuck with on a Mac anyways - but reportedly performance is still great).

All CLI dev tools (including things like Neovim) work out of the box, but also many/most GUI IDEs support working with devcontainers (in this case, the GUI is usually not containerized, or at least does not live in the same container. Although on Linux you can do that also with Flatpak. And for instance GitHub Codespaces runs a VsCode fully in the browser for you which is another way to sandbox it on both ends).

by kantord

3/9/2026 at 10:52:03 PM

This is interesting (and I've seen it mentioned in some editors), but how do I use it? It would be great if it had bubblewrap support, so I don't have to use Docker.

Do you know if there's a cli or something that would make this easier? The GitHub org seems to be more focused on the spec.

by stavros

3/9/2026 at 10:51:15 PM

Can I PLEASE click on ONE post on the front page of HN without immediately being met by some grifter trying to derail it to promote their AI product?

Please? I'm begging here.

by bakugo

3/10/2026 at 12:06:20 AM

Nobody is promoting a product. Simon is just sharing an experiment he attempted. No products being sold here.

by iamjackg

3/9/2026 at 7:08:53 PM

Sorry for the off-topic, but what a bliss to see Windows 2000 interface. And what an absolute abomination from hell pretty much all the modern UIs are.

by blackhaz

3/9/2026 at 10:55:26 PM

My god that interface feels like home.

by stavros

3/9/2026 at 8:05:45 PM

Yeah. Microsoft really went downhill UI-wise.

by shevy-java

3/9/2026 at 10:32:39 PM

win2000 brings back so many good memories.

by diabllicseagull

3/9/2026 at 8:09:26 PM

Is that even remotely relevant to JSLinux?

by cheema33

3/9/2026 at 8:16:46 PM

Yes, it's one of the available emulated systems on JSLinux.

by nout

3/9/2026 at 9:20:47 PM

If you'd clicked the link, instead of just reading the title, you'd have known it was.

by dmd

3/9/2026 at 6:06:21 PM

Unfortunately, he didn't attach the source code for the 64-bit x86 emulation layer, or the config used to compile the hosted image.

For a more open-source version, check out container2wasm (which supports x86_64, riscv64, and AArch64 architectures): https://github.com/container2wasm/container2wasm

by maxloh

3/9/2026 at 6:19:48 PM

https://github.com/copy/v86 might be a more 1:1 fully open sourced alternative.

by zamadatix

3/9/2026 at 6:25:05 PM

Not really. x86_64 is not supported yet: https://github.com/copy/v86/issues/133

by maxloh

3/9/2026 at 9:00:29 PM

Sure, and there are probably some other things lacking, but JSLinux supports a lot more than CLI Linux userspace on x86-64 too. E.g. compare to lack of graphical interface https://github.com/container2wasm/container2wasm/issues/196

It looks like container2wasm uses a forked version of Bochs to get the x86-64 kernel emulation to work. If one pulled that out separately and patched it a bit more to have the remaining feature support it'd probably be the closest overall. Of course one could say the same about patching anything with enough enthusiasm :).

by zamadatix

3/9/2026 at 6:36:34 PM

Incredible guy!

by notorandit

3/9/2026 at 8:10:49 PM

If anyone is interested, I made some modifications last month to get TempleOS running on the x86_64 JSLinux: https://ring0.holyc.xyz/

by AlecMurphy

3/9/2026 at 10:35:57 PM

I love how nonchalantly demonstrates his custom terminal emulator and javascript engine.

by stjo

3/9/2026 at 6:32:26 PM

I can launch this thing and start making arbitrary connections out to port 25 on the internet from some random IP? Hmm.

by wolttam

3/9/2026 at 6:37:27 PM

From the "Technical notes" page:

> Access to Internet is possible inside the emulator. It uses the websocket VPN offered by Benjamin Burns (see his blog). The bandwidth is capped to 40 kB/s and at most two connections are allowed per public IP address. Please don't abuse the service.

https://bellard.org/jslinux/tech.html

by maxloh

3/9/2026 at 6:02:55 PM

I've always been fascinated by this, but I have never known what it would be useful for. Does anyone know of any practical use cases?

by petcat

3/9/2026 at 10:13:34 PM

We are a playful species. People enjoy play. If we didn't have to work for a living but still enjoyed food security that is all most of us would do. But we are also a very exploitative species, some more than others. Companies have made billions of dollars on top of Fabrice Bellard's works, qemu, ffmpeg etc.

These companies don't have any imagination. Their management has no vision. They could not create anything new and wonderful if they tried. People like Fabrice do and we are all richer for it. If your asking about the practical use you are likely in the exploitative mindset which is understandable on HN. The hacker/geek mindset enjoys this for what it is.

by shirro

3/9/2026 at 6:35:53 PM

I use a similar emulator (v86) as a way to share my hobby OS. Approximately zero people, even my friends, are going to boot my hobby OS on real hardware; I did manage to convince some of them to run it in qemu, but it's difficult. A browser environment shows the thing quite well; and easy networking is cool too.

My hobby OS itself is not very useful, but it's fun if you're in the right mood.

by toast0

3/9/2026 at 9:17:46 PM

Some sort of web based archive of applications/etc where you can boot them up in your browser.

by postalrat

3/9/2026 at 9:39:29 PM

That’s what I’d like to use it for as well, but it’s difficult to do so because there’s no way to edit the disk image.

Any advice on how to create a JSLinux clone with a specific file pre-installed and auto-launching would be much appreciated!

by peterburkimsher

3/9/2026 at 10:50:02 PM

Working with VMs always felt difficult because of this. So authoring was built-in to Docker. Now you can use Apptron to author and embed a Linux system on a web page. This aspect is usable, but it's only going to get better.

by progrium

3/9/2026 at 6:19:29 PM

Most such emulators have Internet access on the IP level. Therefore, this is a very cheap way to test anything on the Internet.

    apk add nmap
    nmap your.domain.com
However, the speed is heavily throttled. You can even use ssh and login to your own server.

It can also be used as a very cheap way to provide a complete build environment on a single website, for example to teach C/C++. Or to learn the shell. You don't have to install anything.

by s-macke

3/9/2026 at 10:06:45 PM

You need backend proxies, the browser doesn't allow ignoring CORS by default.

by Onavo

3/9/2026 at 7:05:14 PM

Agentic workloads create and then run code. You don't want to just run that code in a "normal" environment like a container, or even a very well protected VM. There are other options, ofc - eg. gvisor, crossvm, firecracker, etc, but this one is uncommon enough to have a small number of attackers trying to hack it.

by redleader55

3/9/2026 at 7:45:16 PM

What's wrong with a well protected VM? Especially compared to something where the security selling point is "no one uses it" (according to your argument; I don't know how secure this actually is)

by srdjanr

3/9/2026 at 8:51:30 PM

Nothing, but "there are already working options" does not necessarily mean we shouldn't try new (and sometimes weird) things

by g947o

3/9/2026 at 10:44:44 PM

GP says "You don't want to just run that code in ... even a very well protected VM." Why?

by cloudfudge

3/9/2026 at 10:40:19 PM

Yeah but GP was answering to a comment saying "you don't want to run code in a well protected VM". Which is of course complete non sense to say and GP was right to question it.

by TacticalCoder

3/9/2026 at 6:10:45 PM

Maybe if you’ve got some ancient software that’s missing source code and only runs with X Y and Z conditions, you could continue to offer it on the web and build around it like that? Not sure if that would be practical at all, but could be interesting

by varun_ch

3/9/2026 at 6:12:55 PM

My college professor used it to teach us the Linux command line

We have Windows PCs in the classroom.

by maxloh

3/9/2026 at 9:33:55 PM

Similarly I've used it for technical interviews.

by jgtrosh

3/9/2026 at 7:00:20 PM

How do TinyEmu and JSLinux compare to linux-wasm?

From "Show HN: Amla Sandbox – WASM bash shell sandbox for AI agents" (2026) https://news.ycombinator.com/item?id=46825119 :

>>> How to run vscode-container-wasm-gcc-example with c2w, with joelseverin/linux-wasm?

>> linux-wasm is apparently faster than c2w

From "Ghostty compiled to WASM with xterm.js API compatibility" https://news.ycombinator.com/item?id=46118267 :

> From joelseverin/linux-wasm: https://github.com/joelseverin/linux-wasm :

>> Hint: Wasm lacks an MMU, meaning that Linux needs to be built in a NOMMU configuration

From https://news.ycombinator.com/item?id=46229385 :

>> There's a pypi:SystemdUnitParser.

by westurner

3/9/2026 at 8:05:12 PM

He builds epicness.

by shevy-java

3/9/2026 at 7:04:52 PM

UBY: touchscreen: How to scroll the scrollback

by westurner

3/9/2026 at 9:55:50 PM

[dead]

by jccx70

3/9/2026 at 9:51:44 PM

[dead]

by jccx70