install the windows XP mode.

[BillW50]

In

[quoted text muted]
the difference between the two, please don't try to convince people
that there *is* no difference between the two ...

Really? Please educate us all how they are different?

With emulation the CPU/hardware as seen by the guest O/S doesn't
exist and doesn't need to be the same type as the physical
CPU/hardware the [snip]

A Heinlein quote seems apropos here:

"Never try to teach a pig to sing. You'll just waste your time, and
annoy the pig."

Since Stan, you have so far failed to answer any intellectual questions
whatsoever. We must assume you are the annoyed pig. Is this correct? And
I am trying very hard to leave you a huge opening to redeem yourself. As
all you have to do is to act like an intellectual and all is fine.
Although continuing to act like an annoyed pig will not impress us at
all. It is your choice and the ball is in your court now with a opening.
So what will it be Stan?

Here is what I live by Stan.

"People who say it cannot be done should not interrupt the people who
are doing it." -- Anonymous

 

[Char Jackson]

Microwave ovens use a single frequency narrow band TWT, which is a
different critter. For one, it's much more efficient, and the high
production rates have resulted in greatly increased reliability over the
years.

I thought modern microwave ovens used a magnetron. Is a magnetron an
example of a kind of TWT?

 

[Sunny Bard]

"Never try to teach a pig to sing. You'll just waste your time, and
annoy the pig."

Well, I was just trying to help raise the general tone of the group,
lately "we" seem to have shaken off the linux v.s. windows nutters to
some extent (personally I use both) and got round to providing useful
answers to questions, even if half of them seem to deal with email/news
deficiencies in Win7!

 

[Sunny Bard]

Let's go back about 25
years ago. When Commodore released a nifty computer called the Commodore
128. It did something that no other computer before it did (at least
well). And that was it had two processors, a MOS 8510 and a Z80.

The BBC micro pre-dated it by a couple of years and had a second
processor as an option (external rather than built in) though they
didn't share the same address space, one processor acted as a front end
running the peripherals to offload
graphics/sound/disk/tape/serial/keyboard while the other processor had
an almost clean 64K address space for memory and a faster processor
(they shared a small buffer to communicate ISTR).

I'm sure there are plenty of examples within the mini computer world of
systems with front-end processors, such as the 11/780 I mentioned
previously.

So my question to you is... Was this some sort of a virtual machine
having three different OS modes? Or was the C=128 just a C=64 and a CP/M
emulator?

I would say the C=128 was neither an emulator, nor a virtual machine, it
just had multiple processors shoe-horned into one box, and that it was
*compatible* with the original C=64 and with CP/M.

An emulator could run both simultaneously, and I'm not aware of anyone
implementing a hypervisor for 6502 or Z80, pretty difficult without any
privilege rings!

 

[BillW50]

In

With emulation the CPU/hardware as seen by the guest O/S doesn't exist
and doesn't need to be the same type as the physical CPU/hardware the
host O/S is running on (e.g. you can emulate a 6502 processor with
Ohio Superboard II hardware on an i386 based PC, or emulate a VAX
processor with 11/780 hardware on a Motorola based Mac). But in short
the guest code never runs *on* the host hardware.

With virtualisation the guest O/S code actually runs on the host
processor, so the processor seen by the guest must be the same type as
the host. Granted that depending on the type of virtualisation used,
the hardware seen by the guest may either be real hardware that the
hypervisor permits the guest O/S to access or it may be emulated
hardware that is presented to the guest in such a way as to convince
the guest that it is real.

So sometimes virtualisation may use elements of emulation, but
virtualisation is not emulation. Each has its advantages in certain
situations.

Hows that for a 10,000 feet overview?

I see another problem here. As the real Windows XP can run on the
following minimum spec machine:

- Pentium 233-megahertz (MHz) processor or faster
(300 MHz is recommended)
- At least 64 megabytes (MB) of RAM (128 MB is recommended)
- At least 1.5 gigabytes (GB) of available space on the hard disk

http://support.microsoft.com/kb/314865

But the XP Mode requires a much different minimum for the same OS. For
example, I have a bunch of machines here with Celeron and Core Duo
processors. And they *can't* run XP Mode at all. While my Core2 Duo
processors can.

- Windows XP Mode requires an additional 1 GB of RAM (2 GB minimum) and
an additional 15 GB of available hard disk space.

http://windows.microsoft.com/en-US/windows7/products/system-requirements

And the common theme about emulators, is that you are likely not going
to be happy with the performance (speed) unless you have a much faster
than the minimum spec of the real OS that you are trying to emulate. The
exact same thing is true of XP Mode as well. As XP Mode requires about
10 times more power and memory than the *real* XP requires.

And whether you call it a virtual machine, emulator, XP Mode, or
whatever... there are also always some limitations vs. the real OS. But
this is just another con-side of using them, now isn't it?

 

[BillW50]

In

The BBC micro pre-dated it by a couple of years and had a second
processor as an option (external rather than built in) though they
didn't share the same address space, one processor acted as a front
end running the peripherals to offload
graphics/sound/disk/tape/serial/keyboard while the other processor had
an almost clean 64K address space for memory and a faster processor
(they shared a small buffer to communicate ISTR).

I'm sure there are plenty of examples within the mini computer world
of systems with front-end processors, such as the 11/780 I mentioned
previously.

When the Commodore 64 came out, they promised a CP/M option. Well I
forgot all of the details, but Commodore didn't want to release it. I
think some had taken them to court about making promises they couldn't
keep. So they came out with a very limited amount of CP/M cartridges for
the C64. I bought one and it was awful! And it only worked with a very
limited amount of C64 builds. Something about the timing was changed in
later builds and the CP/M cartridge wouldn't work with them. Some claim
Commodore finally made good on their promise with the C128.

I would say the C=128 was neither an emulator, nor a virtual machine,
it just had multiple processors shoe-horned into one box, and that it
was *compatible* with the original C=64 and with CP/M.

An emulator could run both simultaneously, and I'm not aware of anyone
implementing a hypervisor for 6502 or Z80, pretty difficult without
any privilege rings!

How about OS/2 with Windows 3.1? What would you call this? Emulator,
virtual, or what?

 

[Sunny Bard]

I see another problem here. As the real Windows XP can run on the
following minimum spec machine [snip] But the XP Mode requires a much
different minimum for the same OS. XP Mode requires about 10 times
more power and memory than the *real* XP requires.

That may be true, but I bet the XP Mode gets about 9x the performance
out of the 10x faster hardware.

And whether you call it a virtual machine, emulator, XP Mode, or
whatever... there are also always some limitations vs. the real OS. But
this is just another con-side of using them, now isn't it?

You'll note that I already said that each has its advantages, an I
didn't claim neither had any disadvantages

Anyway, I feel we're into pig-whistling territory now, if you don't want
to accept that emulation and virtualisation are *not* the same thing.

 

[Lewis]

You'll note that I already said that each has its advantages, an I
didn't claim neither had any disadvantages

Anyway, I feel we're into pig-whistling territory now, if you don't want
to accept that emulation and virtualisation are *not* the same thing.

Seems to me almost no one understands what virtualization is, and
nearly everyone equates it with emulation.


--
It would be a pretty good bet that the gods of a world like this
probably do not play chess and indeed this is the case. In fact no gods
anywhere play chess. They haven't got the imagination. Gods prefer
simple, vicious games, where you Do Not Achieve Transcendence but Go
Straight To Oblivion; a key to the understanding of all religions is
that a god's idea of amusement is Snakes and Ladders with greased rungs.

 

[BillW50]

In

Seems to me almost no one understands what virtualization is, and
nearly everyone equates it with emulation.

That is because virtualization is virtually the same as emulation.
Worse, many virtual machines out there are actually emulated ones. That
is because emulators are also known as virtual machines.

Emulation usually also emulates the processor through software.
Virtualization cheats in this area by partitioning the processor into
multiple contexts. And both methods slow down the CPU and requires
beefier hardware than just running the real OS alone. Other than that,
virtually no difference.

Hell you don't have to take my word for it. You can also listen to Ben
Armstrong, Virtualization Program Manager for Microsoft. And also read
the comments.

Virtualization versus Emulation... - Virtual PC Guy's WebLog
http://blogs.msdn.com/b/virtual_pc_guy/archive/2004/10/18/243821.aspx