Getting Dirty: What’s Changing Under the Hood

While Windows 7 is a refinement of Vista, this doesn’t preclude making some changes in the kernel and other related systems. Microsoft has opted to spend most of their efforts working on various graphics systems, so among the big changes there’s only a few items of note that don’t fall into the graphics category.

Likely the change with the most immediate impact is that Microsoft has reworked the subsystem responsible for TV tuners, the Broadcast Driver Architecture (BDA). The latest incarnation of BDA adds a full DRM chain, giving rise to the Protected Broadcast Driver Architecture (PBDA). PBDA solves the biggest issue Microsoft has had getting Windows computers accepted as TV viewers: the lack of a simple and effective DRM chain between the tuner and the computer. HDCP ensures that content is protected between the computer and the display, but there has been no standardized way to do the same with incoming content. As such the only services that allow Windows connectivity with protected content thus far have been cable systems using CableCARDs, all the while limiting this functionality to computers specially licensed by CableLabs.


PBDA protected data flow. Slide courtesy Microsoft

PBDA also resolves some lesser technical issues with BDA, such as how a device should communicate with Windows Media Center when it needs setup information that Windows Media Center can’t provide, and how to feed guide data to Windows Media Center (currently it pulls the data from Zap2It). Although this is open to all services, Microsoft’s primary example here is DirecTV, which would require all of these additions. DirecTV has been developing the HDPC-20 tuner for PCs but held it back for unnamed reasons. All indications are that the HDPC-20 will finally be a go due to PBDA (and the addition of H.264 decoding support helps, too).

The downside from all of this however is obvious: more DRM. We’re not fans of DRM, so we’re not enthused to see that yet more DRM is required before content distributors are willing to let Windows computers access their content. It’s very much making a deal with the Devil.

Next up, the Windows kernel has also seen some tweaking in preparation for ever-larger core counts on CPUs. Vista was tuned for up to 32 cores, but the dispatcher lock made scaling beyond that difficult as it causes threads to spend too much time waiting on the lock. The lock has been redesigned to better support more cores, pushing the new cap up to 256 cores. Bear in mind that currently a single Intel Nehalem quad-core processor effectively has eight cores due to Hyper-Threading, so it was possible to hit the 32 core limit on a 4P Nehalem system, directly creating a problem once Intel puts more cores into Nehalem’s successor. With the limit raised to 256 cores, Windows 7 should be well ahead of the CPUs again.

SSD users will be happy to know that Windows 7 has improved support for those devices. Although Windows 7 doesn’t have an SSD-optimized file system as first rumored, it is adding TRIM support. For more details on TRIM, please see our SSD Anthology article

Wrapping up the changes, Microsoft has also added native support for Wireless Wide Area Networks (WWAN), more commonly referred to as mobile broadband networks. Adapters for such networks were already usable on existing Vista and XP installations, but this brings the configuration of those devices into the OS rather than using 3rd party utilities, similar to how Windows took over WiFi management previously.

Further optimizations have also been made under the hood to help contain Windows’ resource usage and speed up its boot time. Microsoft hasn’t documented every single change they’ve made to make Windows less resource hungry, but there’s clearly a cumulative effort beyond just squeezing more out of the DWM and gadgets (more on this later). Meanwhile everything that makes Windows less resource hungry feeds into shaving seconds off how long it takes to boot Windows, which along with other changes is designed to help get Windows to consistently boot in under 30 seconds. Changes here include additional parallelism in driver initialization and chopping down the number of services that load with the system before they’re ever called. SuperFetch has also been slightly tweaked to improve the post-boot experience – it no longer starts caching things immediately after the user account loads, so that using a freshly booted computer isn’t quite so sluggish. In effect SuperFetch has been deprioritized some so that its loading is less noticeable to the user.


Vista SP1 Boot Times, Courtesy Microsoft

7? Getting Dirtier: Graphics
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  • Bmadd - Wednesday, May 6, 2009 - link

    I see the graphs, i see the new features and i honestly cant be the only person who doesn't want to change from my Vista x64 install? Can i? i got a dual core and 4gig of ram, a dash of tweaks and moving the pagefile and everything loads within a second of running. I personally dont see how going from vista to 7 for me can be a thought when there gonna give me the only thing i care for in 7 and thats DirectX11 and the new aero features. Thanks MS
  • Sazar - Wednesday, May 6, 2009 - link

    Why not?

    It's free to use and try. If you don't like it, go back.

    I have switched both my HTPC and my main rig to Windows 7 simply because it is a more efficient way for me to work. The homegroups sharing features is miles better than the old, archaic sharing method and the new Media Center interface is fantastic.

    Also, Windows 7 loaded up all the drivers I needed by default, including both of my Hauppauge TV Tuner drivers and it just worked.

    I see a lot of naysayers nit-picking, which is fine. However, I have yet to see anyone point out anything meaningful that should disuade people from either using Vista or Windows 7.

    Btw, for me, the biggest selling feature, beyond the vastly improved 10 foot interface in MCE, was Aero Peak. Can't go back to Vista now without that functionality :)
  • Bmadd - Wednesday, May 6, 2009 - link

    Well i have never really used gadgets, widgets and such. There not for me like myspace and twitter aren't for me. I would hate to change to win7 after setting me vista install up so nicely only to not like it and have to spend time getting it back to the sleak thing it is at the moment.

    Perhaps i will download the RC and just keep it there till Win7 is released and drivers are all sweet, install RC on a new hard drive and go from there but i am fair to pleased with my current vista install to consider changing
  • papapapapapapapababy - Wednesday, May 6, 2009 - link

    not a single feature that i want or even care about. how about a good competent fast image viewer? more drm? giant icons? no classic ui? terrible. just give me a smaller, faster, stronger and more efficient xp or gtfo ms.
  • TonkaTuff - Wednesday, May 6, 2009 - link

    Microsoft should count themselves very lucky that Apple remains uninterested in being the OS for everyone and restrict themselves to the premium OS and hardware market.

    Yeah Snookie Im sure apple holds themseves back from over 90% of the O/S market based on there morals and lack of interest in making more money. What kind of deranged fanboy are you? Comments like the one above show how brainwashed some of you looney tunes are becoming.
    It really is scary and you should seek professional help.

    A comment in the article really hit the nail on the head,

    MANY PEOPLE SAY THEY HATE VISTA BUT FEW CAN ACTUALLY SAY WHAT THEY HATE ABOUT IT.

    Yeah Vista had issues when it first was released, it was a major step from the XP O/S but that was 2 bloody years ago. Ive been running Vista on my Gaming rig and my Work Laptop and a server/seed box and in 12 months I havnt had 1 crash that was the O/S's fault, Not one crash, not one BSOD, probably 4 or 5 freeze ups that had to be end tasked in 12 months on 3 systems numbering well over a 1000 hours of use, not even XP could claim to be that stable.

    Like any O/S it has its annoyances, they all do (yes snookie even your precious mac).

    Do I expect Win7 to be much different from Vista? No not really, I expect it will be a dressed up and refined version of Vista.

    Why would Microshaft do such a thing, they just want more money, why not release it as a service pack for Vista?
    BECAUSE THEY HAD TO CHANGE THE NAME AND MAKE IT OUT TO BE DIFFERENT FROM VISTA BACAUSE OF ALL THE LEMMINGS OUT THERE THAT HATE VISTA BUT DONT KNOW WHY THEY HATE IT!!!!!!!!!!!

    End of rant.......Snookie you sir are a sychotic applemac fanboi, get help for god sake.
  • squeezee - Wednesday, May 6, 2009 - link

    Microsoft has said to developers (at PDC at least) that Direct2D and DirectWrite along with the rest of DirectX 11 functionality will be available on windows Vista.
  • fendell - Wednesday, May 6, 2009 - link

    Has anyone tested Windows 7 and Ventrilo (any version) over some time?

    It's the only thing that keeps me on 64bit XP at the moment, because ventrilo has this weird behaviour on windows 7 where it suddenly doesnt recieve data for 2-5 minutes, then suddenly gets everything at once, this is veery frustrating and in fact raidbreaking in wow ;)
  • nycromes - Wednesday, May 6, 2009 - link

    I have also used Windows 7 RC for WoW raiding and have had no major issues. Ensure you are running it as an administrator. I had a few issues before doing that, but none like you are describing. I am using a USB microphone and a standard soundcard speaker combination with no issue.
  • vectorm12 - Wednesday, May 6, 2009 - link

    I use ventrilo for wow a couple of times per week, at times for hours without any issues on build 7077x64(correct me if I'm wrong, found on piratebay.org btw). However I do use a USB connected wireless Microsoft headset(looks like the 360 one but grey) which might have some impact as it works like a second soundcard.
  • snookie - Wednesday, May 6, 2009 - link

    If you think XP is the best OS ever then you haven't used very many. It is archaic.

    "The biggest news is that the Ultimate/Business/Home Premium schism has been resolved with Windows 7."

    This is a pretty amazing statement seeing as how it took a further paragraph to partly but not fully describe what all the versions are for.

    The Start Menu remains a horrible user interface designed by committee. Just awful.

    Windows 7! Now with even more DRM!!!

    UAC is an attempt to place responsibility for security too much on the user which is why it was so intrusive. A certain amount of user action is reasonable but UAC went far beyond that.

    WTF, why does IE 8 take up so much space with its headers? Seriously Microsoft do you have no idea at all about usability? Slapping a ribbon interface on a simple text processor is just dumb.

    Mail, Calendar, and Movie Maker might as well have been removed because they suck. But their removal points out even more how Microsoft needs its own version of iLife.

    ISO implementation is so Microsoft. Half-ass as usual.

    Why does Windows 7 need a disk defragmenter in 2009? No other modern OS does.

    Virtual Windows XP? Is this a joke? Probably won't run on older machines which is where it is needed most and even more headaches for desktop admins for configuration and administration.

    Why would you do performance testing on an SSD drive which very few desktop boxes have these days?

    Looks like Windows 7 will suck on laptops as much as Vista does. Not good news since so many notebooks are sold these days.

    My recommendation to Corporations is that for the 95% of users who need basic functionality they replace Windows entirely with a locked down Linux of some form. Many that I have worked with are considering this very thing and I have no doubt the Windows 7 will hasten this decision. XP requires far too intensive support ( yes i know your handbuilt game tower never has to be rebooted with XP, sure it doesn't).

    Microsoft should count themselves very lucky that Apple remains uninterested in being the OS for everyone and restrict themselves to the premium OS and hardware market and that an unrestricted Linux desktop is still to complicated for most users. more and more companies are providing their high end IT Architects and Developers with Macs and they are happily snapping them up. I have seen this at Cisco, Oracle, Motorola, and may others. When Visual Studio using .NET developers would rather use a VM on OS X t do their development there is something very wrong and I'm seeing a lot of that.

    The authors really do not understand the relationship between development tools, threads, the kernel, and processor usage.

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