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Comment by zoobab

6 months ago

"Looks like each container gets its own lightweight Linux VM."

Not a container "as such" then.

How hard is it to emulate linux system calls?

27 comments

zoobab

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teruakohatu  6 months ago

> How hard is it to emulate linux system calls?

It’s doable but a lot more effort. Microsoft did it with WSL1 and abandoned it with WSL2.

  • tsimionescu  6 months ago

    Note that they didn't "do it" for WSL1, they started doing it, realized it is far too much work to cover eveything, and abandoned the approach in favor of VMs. It's not like WSL1 was a fully functioning Linux emulator on top of Windows, it was still very far from it, even though it could do many common tasks.

    • benwad  6 months ago

      I've always wondered why only Linux can do 'true' containers without VMs. Is there a good blog post or something I can read about the various technical hurdles?

      18 replies →

NexRebular  6 months ago

> How hard is it to emulate linux system calls?

FreeBSD has linuxulator and illumos comes with lx-zones that allow running some native linux binaries inside a "container". No idea why Apple didn't go for similar option.

  • citrin_ru  6 months ago

    FreeBSD Linux emulation is being developed for 20 (may be even 30) years. While Apple can throw some $$$ to get it implemented in a couple years using virtualisation requires much less development time (so it’s cheaper).

  • rcleveng  6 months ago

    Apple's already got the Virtualization framework and hypervisor already (https://developer.apple.com/documentation/virtualization), so adding the rest of the container ecosystem seems like a natural next step.

    It puts them on par with Windows that has container support with a free option, plus I imagine it's a good way to pressure test swift as a language to make sure it really can be the systems programming language they are betting that it can and will be.

    OrbStack has a great UX and experience, so I imagine this will eat into Docker Desktop on Mac more than OrbStack.

  • masklinn  6 months ago

    Because that‘s a huge investment for something they have no reason or desire to productivize.

surajrmal  6 months ago

syscalls are just a fraction of the surface area. There are many files in many different vfs you need to implement, things like selinux and ebpf, iouring, etc. It's also a constantly shifting target. The VM API is much simpler, relatively stable, and already implemented.

Emulating Linux only makes sense on devices with constrained resources.