>>> So when you say "works on any reasonably modern PC", what you 
>>> *actually* mean is "works on any brand new bleeding-edge PC"?
>>
>> No. I believe it was the 386 that added the capability.
>>
>> You know, two generations back before the Pentium came out?
>>
>> Added primarily to emulate multiple "DOS boxes" under Windows.
> 
> The 386 or so added "virtual mode" (or whatever the exact term is) that 
> makes the CPU act as if it's in real mode, but it's really in protected 
> mode, and the OS can control the page mappings and so forth.

"Virtual real mode".

http://en.wikipedia.org/wiki/Virtual_8086_mode

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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> Nope, I was wrong. Apparently it uses a 4 MHz customised Z80 with an 
> on-die ROM for bootstrap and a customised instruction set somewhat similar 
> to the Intel 8080... Oh well!

Oh and Wikipedia tells me the TI-86 has a 6 MHz Z80, so I guess not straight 
copy of game-boy apps, some hacks probably needed for timing etc.  Or maybe 
the games just ran a bit 50% faster, I can't remember.

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Invisible wrote:
> PS. Yes, I'm playing Doom at work. And? ;-)
> 
S0 you are human after all :-)

John

-- 
"Eppur si muove" - Galileo Galilei

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Doctor John wrote:
> Invisible wrote:
>> PS. Yes, I'm playing Doom at work. And? ;-)
>>
> S0 you are human after all :-)

Actually, in truth I was watching the demo. The framerate is a bit too 
low to actually "play" the game. (Plus I don't know the controls.)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Invisible wrote:
> Doctor John wrote:
>> Invisible wrote:
>>> PS. Yes, I'm playing Doom at work. And? ;-)
>>>
>> S0 you are human after all :-)
> 
> Actually, in truth I was watching the demo. The framerate is a bit too 
> low to actually "play" the game. (Plus I don't know the controls.)
> 
IIRC the key bindings are configurable. OTTOMH <ESC> in the splash 
screen pulls up a menu and I think options in that menu leads you to key 
bindings. Don't quote me on that though

John

-- 
"Eppur si muove" - Galileo Galilei

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"Invisible" <voi### [at] devnull> wrote in message 
news:48bd22a1$1@news.povray.org...
>>
> That still leaves open the question of how some products claim to 
> virtualise without emulation on CPUs that lack this technology.
>

Quote, from the wiki page you linked

"VMware and similar virtualization software for the x86 must employ binary 
translation techniques to trap and virtualize the execution of certain 
instructions. These techniques incur some performance overhead as compared 
to a VM running on a natively virtualizable architecture"
http://en.wikipedia.org/wiki/Binary_translation

Also see
http://en.wikipedia.org/wiki/Operating_system-level_virtualization

The hardware extensions is what makes the hypervisor type products (that run 
'beneath' the OS possible). You'll need that for things like Server 2008's 
hyper-V, VMWare's ESX server (which can make do without), Xen and others.

Things like VMWare workstation can use it but don't need it. MS's Virtual PC 
can't use the hardware emulation at all, though Virtual Server can

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Gail wrote:

> Quote, from the wiki page you linked
> 
> "VMware and similar virtualization software for the x86 must employ 
> binary translation techniques to trap and virtualize the execution of 
> certain instructions. These techniques incur some performance overhead 
> as compared to a VM running on a natively virtualizable architecture"

Right. So it only emulates some instructions, instead of all of them?

> The hardware extensions is what makes the hypervisor type products (that 
> run 'beneath' the OS possible). You'll need that for things like Server 
> 2008's hyper-V, VMWare's ESX server (which can make do without), Xen and 
> others.
> 
> Things like VMWare workstation can use it but don't need it. MS's 
> Virtual PC can't use the hardware emulation at all, though Virtual 
> Server can

I've spent some time looking at all the various products out there. It 
seems that QEMU is the only one that can be run without "installing" 
anything. Some install special kernel-mode drivers, others run on the 
bare metal beneigh the first "privilaged" OS, but I'm not seeing 
anything else that you can throw on a USB stick and use anywhere. (I 
also note that several of these things appear to be "based on" QEMU...)

Still, if I was trying to offer hosting of virtual servers, this would 
be a non-issue.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Invisible wrote:
> You can use that to make real mode applications (e.g., DOS programs) 
> think they have the machine to themselves. But that doesn't work for a 
> protected mode program such as an OS.

I stand corrected. :-)

-- 
Darren New / San Diego, CA, USA (PST)

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Darren New wrote:
> Invisible wrote:
>> You can use that to make real mode applications (e.g., DOS programs) 
>> think they have the machine to themselves. But that doesn't work for a 
>> protected mode program such as an OS.
> 
> I stand corrected. :-)

Some of us have actually *read* the IA32 reference manual. ;-)

[OTOH, I guess some others have written actual IA32 programs, so...]

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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On Sun, 31 Aug 2008 14:46:44 +0100, Orchid XP v8 wrote:

> OK, so I realise I'm probably about 20 years behind everybody else, but
> seriously... this is THE coolest thing I've seen this year! I would
> never have believed it was physically possible - and certainly not
> without spending hours setting it up. I can't get over how EASY this
> was!

Told ya that Virtualization was useful. :-)

Jim

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