[apignotti]

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.

[aidanhs]

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!