Re: [Qemu-devel] International Virtualization Conference

[Jim C. Brown]

On Tue, Oct 10, 2006 at 10:03:26PM -0400, Rob Landley wrote:
> > That is not how he uses the terms. He uses them interchangably.
> B) The people I've seen care about this are embedded system developers, who 
> also make a distinction between "emulator" and "simulator".  (One is a 
> hardware board that fakes a certain processor, the other is software that 
> does the same thing.  Sometimes, I can even keep them straight.)

They use it differently than we do. See below.

> 
> > I was just trying to make clear the difference between emulation and
> > virtualization. 
> 
> I consider this difference an implementation detail that's likely to vanish 
> into obscurity as time goes on.

The difference between floppy disks and USB flash sticks are likely to vanish
into obscurity as time goes on. Doesn't mean floppy disk designers would get
invited into USB flash sticks conferences (unless they also designed USB
flash sticks).

The way cpu emulation is done in bochs/qemu-softmmu and the way its done in 
VMware/VirtualPC/etc represent different (though related) software technologies.

The end user doesn't care as long as its fast enough and accurate enough to run
what they want, naturally. Why should they? But developers at a major conference
probably would. They should be able to keep their technology straight.

> 
> Modems wandered back and forth between hardware and software before dying.  
> Hardware crypto accelerators were really popular a few years back.  One of 
> the promises of the cell chip is doing stuff like 3D rending and mp4 
> compression entirely in software at a reasonable speed. 

So?

> And now it's 
> only "virtual reality" if you use an actual 3D graphics chip, with software 
> rendering it's just "emulated reality".  Right.

Virtualization != virtual, so I can't respond to this statement as you wrote it.
I have no idea what "emulated reality" means and I can't see the relationship
between "virtual reality" and "virtualization" other than the fact that both
start with the same 7 letters and the fact that both run on computers.

If I clarify it like this,

: And now it's 
: only "virtualization reality" if you use an actual 3D graphics chip, with 
software 
: rendering it's just "emulated reality".  Right.

then it makes even less sense.

Quite simply, you are comparing apples to oranges.

Virtualization has nothing to do with virtual/emulated/simulated. Virtualization
refers to running cpu instructions in the guest OS on the host OS's cpu. The
meaning is quite specific here. Do not confuse virtualization with virtual.
They mean two completely different things.

> 
> The "this must be done in hardware to get reasonable performance" people are 
> always amusing, in retrospect.  Personally, I've never bothered to even 
> install kqemu.

Same here. Of course no one is talking about that ... (the fact that qemu
exists is proof that the statement is false imvho).

> 
> Rob
> -- 
> "Perfection is reached, not when there is no longer anything to add, but when 
> there is no longer anything to take away." - Antoine de Saint-Exupery
> 

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.