On 4 February 2013 21:08, Alexander Lazarević <laza at e11bits.com> wrote:
> Hi!
>
> Just to get myself up to date on the latest. Is it still true, that we got
> three independent VMs?
>
> 1. Interpreter VM
> 2. Stack VM
> 3. Cog
>
> So as I recall the Stack VM was planned to replace the Interpreter VM
> entirely. Or are there any cases were one only could use an Interpreter VM
> (or cog)? Or is the Stack VM the all versatile VM by now? What are the
> requirements for cog to run?

If you have a 64 bit machine and no way to install 32 bit libraries
(Heroku, say), then Interpreter VM is your only choice. (Or, 32 bit
libs are a requirement for Cog.)

> It might not come as a surprise, but I haven't looked into the VM code
> lately. But I recall that the linux VM at least uses the modules framework
> to have different display, sound, etc. plugins for the VM. I don't know how
> interleaved the VMs from above are, but would it be out of scope to have
> _one_ VM that could have different object engines as VM plugins? So the VM
> could check the architecture it's running on and the image that should be
> loaded and decide on that what object engine to load/use?

I'll leave it to others to answer definitively but I suspect the
answer is that while you can share the codebase to a large extent, you
can't have a cross-platform binary. Squeak does run on at least OS X,
Linux, FreeBSD, Windows, RISC OS.

frank

> The obvious benefit for the enduser I see is: *There is only one VM !*
>
> The benefit for VM developers might be that they only need to focus on the
> object engines and they would share a common VM frame.
>
> This might be a "well yes, but too much work" thing, but nevertheless it's
> something I would like to share.
>
> (If turns out that the energy would better invested into something
> different, there is also the possibility to use the package system on debian
> derived systems, that would take care to install the right VMs on such
> system, so that the enduser wouldn't need to worry about this. And I guess
> there is a similar mechanism for windows and mac)
>
> Alex
>
>
>