

Secret No More: Revealing Windows XP Mode for Windows 7 - halo
http://www.withinwindows.com/2009/04/24/secret-no-more-revealing-windows-xp-mode-for-windows-7/

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TomOfTTB
It's a good move for Microsoft but kind of a sad statement on the computer
industry in general.

Let me preface this by saying I make the purchasing decisions for my agency so
I'm as guilty as anyone. But the reality is we're all kind of lazy. Developers
don't want to rewrite their programs, IT admins don't want to learn Linux and
all in all people just want to tow the line. But with x64 processors becoming
mainstream and Microsoft pressuring hardware makers not to offer XP drivers we
as an industry all have to upgrade to something.

That will essentially be the basis for Windows 7's sales and that's why this
feature is both a good idea and a depressing statement on us all.

~~~
potatolicious
IMHO the problem is not that developers don't want to rewrite their programs,
it's that they don't want to _maintain_ them, and don't want to _learn_.

There's no problem with letting old software stop running at some point,
provided said period is long enough. The problem with Windows and its back-
compat is that it supports more than legacy apps - many developers release
_brand new applications_ that still rely on long-deprecated API and
technologies. This complicates back-compatibility, since removing API will now
kill new apps instead of just the decade-old ones it's meant to target.

Developers need to get a lot less lazy - if the API says "deprecated", do NOT
use it. Do _not_ use undocumented calls... If people started programming
instead of layering on hacks, this wouldn't be a large problem.

~~~
yters
simple solution: microsoft releases as scan utility that counts the number of
unique deprecated calls. The higher the count, the more costly the software
maintenance, and the less preferable it is. so, all companies can
independently evaluate a piece of software and developers can't hide their
shoddiness.

~~~
potatolicious
Companies often do - I've worked for shops that _knew_ a rewrite was a good
idea, and that hacking layers of old API onto their product was a bad idea in
the long run.

But management isn't always focused on the long run.

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barrkel
I wonder about DirectX / video-intensive compatibility.

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DenisM
VMWare workstation plays video perfectly in WinXP VM, I don't see a reason why
MS couldn't do the same.

~~~
mlLK
VirtualBox doesn't. =/

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mpk
Linux and OSX have had a number of ways to pull this off for ages. I don't
really consider the idea the MS is doing this on their own stack a big
surprise.

What still surprises me is that it took the Open Source community to provide
full DOS execution on modern systems by means of DOSBox (which basically
emulates a DOS era x86 system) instead of the hack-it-up route MS took for
Win95 and pretty much abandoned on the road to XP.

Contrast that with other companies (say, IBM and SUN) which have binary
compatibility going back to the early 80s and beyond..

~~~
briansmith
Windows XP still supports 16-bit Windows 3.x applications. Sun's backward
compatibility guarantee goes back to SPARC7 (circa 1987) which was already
32-bit. Windows 3.0 was 16-bit and was released in 1990. I don't know about
IBM but I imagine the situation is similar. Linus didn't even start Linux
until 1991. Desktop Mac OS X was released in 2001. Microsoft's compatibility
achievement there is much more impressive to me.

AFAICT, the primary reason for this compatibility mode is to run IE6 side-by-
side with IE8, so that corporations don't have to upgrade their web apps all
at once. Neither Linux nor Mac OS X offers that feature for _free_ ; you can
virtualize XP in Linux and Mac OS X but you don't get a free XP license with
them.

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wmf
I can only imagine the bloat of running a complete copy of XP under 7 for app
compatibility. The blue box worked for Apple, though.

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Hexstream
Virtualization technology is surprisingly efficient. Besides, XP is likely
much less resource-intensive than Windows 7.

~~~
wmf
But what's the definition of efficient? Will XP use less RAM in a VM than it
would on hardware?

~~~
derefr
I imagine it won't use much at all: it's a special copy of XP, in a specially-
written VM, running on a single platform. They can likely get memory
management, and other crazy things, to fall through to the host OS.

I hope, though, that they're not trying to make XP applications as secure and
trustworthy as W7 applications by wrapping them in a slow software condom;
that, instead, they're just trying to ensure backwards-compatibility to the
utmost extent possible. If something could crash XP, it should be able to
crash W7 transparently through VXP—that's the level of entanglement where you
start to see real performance. The users who need the old applications, that
ran on XP but don't run on Vista, know what the bugs are; they'd rather have
the _same_ bugs, with the same symptoms, than _new_ bugs. They know what
they're getting into when they install something in XP-virtualization mode, so
we don't have to _improve_ the experience beyond what it was like in XP just
for them. That's what releasing a W7 version is for.

~~~
bonaldi
"If something could crash XP, it should be able to crash W7 transparently
through VXP"

Pretty sure users are going to be willing to give up a degree of entanglement
to both be able to run their XP apps _and_ have a system that doesn't crash.
That alone would be an incentive to upgrade to W7.

Classic on OS X worked the same way, too: a Classic app could take down the
entire Classic environment, but OS X would safely charge on apace. This was
definitely something that helped drive people to upgrade.

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blogimus
FTA: _Now, they can claim almost complete Windows XP compatibility, or almost
100 percent compatibility with all currently running Windows applications._

It'll be interesting to see what software that currently runs on XP fall
outside of the "compatible" line.

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s3graham
Is it sandboxed? Or does it have free-ish reign of the user's resources?
Meaning indefinite patching of XP, assuming that there'll be a substantial
enough target for XPM-specific malware?

(ps IE6 4EVA! Really, now.)

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celticjames
Rather than virtualization, I'd prefer to see something like WINE. You would
think that Microsoft would be able to write translation layer without the
overhead of a virtual machine.

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smhinsey
this is potentially huge over the long run, as the article implies, but to
state it more clearly, it frees future versions of windows from a significant
degree of the legacy burden borne by the line up to version 7. not only does
this give microsoft more flexibility with windows, it gives them a plausible
roadmap for a transition to midori, or whatever is eventually declared the
platform of the future.

