Urban legends are strange creatures. Even when they're exposed for what they are - tall tales seemingly "legitimized" through frequent retelling - people continue to believe the lie.

Case in point: "MinWin." For months, so-called industry "experts" were speculating that Microsoft would make a clean break with Windows 7 - that core elements of the OS would be rewritten from the ground up and that backwards compatibility would be relegated to the domain of virtual machines and emulation.

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Central to this theory was "MinWin." Citing the now infamous "Eric Traut demo," they claimed as fact that Microsoft was retooling the Windows kernel to make it lighter and less monolithic. Never mind that doing so would likely break the entire Windows hardware/software ecosystem. "MinWin" was the future. It was new. It was "cool." And as any industry media professional will tell you, it's the "cool" new technologies that drive page views.

Of course, now we know better. The whole "MinWin" bubble burst last week when, through various Microsoft web postings and interview comments, it was revealed that Windows 7 would in fact be more akin to "Windows Vista Second Edition": An evolutionary update that builds upon the existing NT 6.x kernel architecture as manifested in Windows Vista.

Undaunted, the "MinWin" true believers continue to cling to the legend. "If not Windows 7, then some future version," they say. "MinWin is coming." In fact, it could be here "today" if Microsoft would just "strip away all the user-mode bloat they've tacked onto Vista and its derivatives."

That last point seems to be a common theme among the "MinWin" faithful: That if you could somehow "pare down" Vista, removing unnecessary background services and dumping all that flashy Aero baggage, you'd end-up with a much leaner OS, something comparable to Windows XP or even 2000. It's an intriguing idea, one that adds to the whole "MinWin" mystique. It's also patently false.

The truth is that, when you strip away all of the new services and UI flashiness, the core Windows Vista/7 architecture is still quite bulky - much more so than Windows XP and/or 2000. People who claim otherwise simply haven't done their homework. Fortunately, we make it easy to do just that by providing tools and resources of the Windows Sentinel project

For example, if you start with a basic Windows Vista Business (SP1) installation, you are looking at a workload consisting of nearly 600 threads spread across some 60+ processes. Whittle this down a bit - by disabling Superfetch, Indexing, ReadyBoost and a few other non-critical services - and you can get the thread count down into the 450-500 range, 98 of which are, incidentally, owned by a single process: System (i.e. the Windows Vista "kernel").

By contrast, a default Windows XP Professional installation spawns just over 300 threads across roughly 40 processes. Whittle this down a bit and you can get the thread count well under 300. Cut the OS to the bone and you can get it into the low 200 range spread across 20 or fewer processes, with 57 of those threads belonging to the Windows XP kernel process (i.e. System).

Compare this to Vista which, when cut to the bone (every non-critical service disabled, all UI goodies turned-off), still spawns 41% more (340 vs. 241) threads spread out across 50% more (30 vs. 20) processes, and you see how much harder it is to put Vista on a "diet." The Vista kernel alone spawns 72% more (98 vs. 57) threads than Windows XP.

Even Windows 2008 running in its "Server Core" configuration - a scenario often cited as a precursor to "MinWin" - still spawns roughly 300 threads, and it doesn't even have a proper shell running (just a command line). And, of course, the "Server Core" kernel accounts for 98 of those threads - just like Vista SP1.

Given the above, it really comes as no surprise that, even stripped bare and with all the extraneous UI fluff disabled, Vista still takes 40% longer to execute the OfficeBench test script when running against an identically configured Windows XP system (Office 2007 used in both test scenarios). You can't have your cake and eat it too. More concurrent threads (especially in the kernel) equal more potential CPU overhead, impacting linear performance.

Bottom Line: The idea that Vista's problems are entirely isolated to User Mode is pure rubbish. Vista is fatter all the way around, and this includes the kernel and its various outlying critical subsystems. To achieve anything close to "MinWin" you'll need to break all sorts of stuff that would render Windows essentially unusable. Which is why, despite all the fanfare and breathless pontificating, "MinWin" remains an academic exercise - and why the bloated Windows Vista/7 kernel architecture, with its DRM hooks and bulky legacy constructs, is here to stay. Get used to it.


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