[OT] Virtualization (WAS: UNIX V7)

[Liam Proven]

2009/6/12 Pontus Pihlgren <pontus at update.uu.se>:
> On Fri, Jun 12, 2009 at 08:40:19AM -0700, Cameron Kaiser wrote:
>> I agree, but then there's also the dividing line between a VM and
>> virtualization. Actually, I'm not surprised to hear that some emulation
>> had to be done for x86 originally -- the ISA certainly doesn't lend itself
>> well to virtualizing out of the box ;-)
>
> Someone told me that VMware still emulates some of the instructions that
> could be virtualized either because they are buggy or slow. Don't take
> my word for it though.

As far as I know, VMware still doesn't use the hardware emulation in
modern Intel & AMD chips. They firmly believe that their own approach
is more powerful and offers better performance.

I believe VirtualBox also has its own, different approach to x86
virtualisation, involving forcing Ring 0 code in guests into the
seldom-used-on-x86 Ring 1, whereas user code normally runs in Ring 3
or something. I am not an expert in the minutiae of this stuff, I'm
afraid.

(Although when I interrogated Connectix about VirtualPC about 10y back
(with my journalist hat on) they were so thrown by my deep-tech
questions that they flew Jon Garber, the Connectix founder and chief
scientist, over the Britain to talk to me. That was fun and very
interesting indeed.)

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