Hacker News Reader

Comment by apignotti | Hacker News Reader

Hello HN! Lead dev of WebVM and CTO of Leaning Technologies here.

Happy to answer any question.

All the emulation of desktop machines in WASM I've seen so far have been for x86 - do you think there are significant additional hurdles for x86_64? Or is it just a matter of time?

Separately, one bit of feedback - it's cool that webvm is open source, but I think it's fair to ask you to be upfront that cheerpx itself is not (which is fine!) in the blog post itself where you talk about webvm licensing. If I wasn't already familiar with the wasm emulation space I would have felt rather misled.

I cannot speak for other VMs, in the case of CheerpX there is nothing fundamental preventing emulation/JIT-ting of 64-bit platforms, but it is an inefficient choice due to the current limitations of Wasm, in particular on the front of how much memory can be used in total. In the best case scenario it would be 4GB, but it's unlikely this can be achieved on all devices in the real world.

64-bit code by its nature consume more memory, each pointer is twice the size, which makes the memory limitation even more pressing for no advantage. Please note, that this is unrelated to the work on WebAssembly Memory64. The issue is not the lack of address space, but rather on the actual memory that can be allocated in practice.

For this public deployment of WebVM we have chosen to limit the maximum memory to 700MBs, which makes the demo work fine on the vast majority of devices, including mobile ones. This said, we do plan to support the 64-bit ISA in the future with the main use case of supporting all the existing docker images available on Docker Hub and similar platforms.

Appreciate your feedback on licensing and we will take it into account, but please notice that this article is specifically about WebVM, that is indeed FOSS. A separate article dedicated to the CheerpX 1.0 release will be published soon, and it will of course be very clear that the latter is proprietary.

Interesting, that's helpful, thanks - so with the eventual arrival of memory64 and assuming I only wanted to target desktop systems and assuming browser implementations permit large allocations (e.g. 8GB) - large 64bit apps could work fine. I have a use case for this I've been poking at for a bit, but implementing my own version of cheerpx would be a lot of work, maybe I'll just wait!

On open source - I can only give you feedback as an outside fresh pair of eyes :) I incorrectly interpreted that it was full stack OSS based on the overall blog post 'vibe' and had to deliberately double check because I was aware of cheerpx beforehand. Perhaps it's just me. I look forward to the cheerpx blog post!

This looks amazing, congratulations! I can see that it seems to run offline (curl says "# requires networking"), but if I launch it on airplane mode on an iPhone it halts. Is this the expected behavior? Also, is it possible to install packages? These two things could address some of the shortcomings of iSH. Thanks!!

The disk blocks are streamed on demand, so a connection is required.

The virtual disk is quite large (1.5GB) which is necessary to run a full distro but makes pre-downloading for offline mode not possible.

It _could_ work if you let your workload run once and then disconnect, but there is no guarantee.

Installing packages is supported both in the Debian terminal and Alpine desktop.

It is certainly possible to download and store 1.5 GB in browsers these days.

I’m glad that y’all are collaborating with GOG to get games running in the browser - I hope being able to ship fully emulated environments helps give some older games, that might have compatibility issues, a larger audience!

Do you have any other industries in mind that you think might be interested in CheerpX?

I want to clarify that we are not officially collaborating with GOG at this time, although we would love to do so.

We think CheerpX would be very useful in education, to provide ready-made environments for students that can be wiped out on demand. We also envision it to be an alternative to remote virtualization (e.g. Citrix) in the enterprise sector.

What are some other applications of WebAssembly that you find promising?

The promise of WebAssembly is bringing actual large scale applications to the browser.

To be clear, it is possible to build large apps with technologies like TypeScript, with VSCode being probably the standard bearer of this approach, but at Leaning Technologies we don't believe this solution to be viable for everybody.

We strongly believe that more "traditional" languages are required instead to work at scale, especially C++ and Java, and we offer products dedicated to these languages as well: Cheerp and CheerpJ respectively.

Although these languages might not be the most exciting ones, they have a proven track record for delivering large scale applications used by millions of people. Billions of people if the Operating Systems we all use are taken into account.

Thanks to WebAssembly these robust and scalable languages can be used to build Web apps. My own personal metric for the success of WebAssembly is seeing AAA games delivering playable demos as Web apps by cross-compiling (a portion of) the game to the browser.

Amazing work!

How's performance?

Can I run any distros on WebVM?

Performance is expected to be between 3x-10x slowdown depending on the workload, which for this class of systems is quite good. The gap, especially on the high end, will further shrink as the virtualization engine improves.

Not all parts of the ISA are as well optimized currently. The codegen for integer operations (the most common by far) is very sophisticated. Floating point and vector operations still have a pretty basic implementation.

WebVM can run any distro, barring bugs in our syscall layer of course :-)

You can add your own Dockerfile and deploy a custom version on GitHub: https://github.com/leaningtech/webvm/?tab=readme-ov-file#for...

Nice, thanks for the info!

Reply on news.ycombinator.com