Thoughts on the Longhorn Driver Model

The x64 launch aside, we have heard about some very interesting hardware refinements that Microsoft wants to see happen by the time we reach Longhorn availability. As Gates mentioned in his keynote, the Longhorn driver model is finished. This means that hardware vendors can begin making sure their hardware will run smoothly under Longhorn today. It also means that we are able to catch a glimpse of what things will be like when Longhorn finally comes along.



One of the most interesting things to us is the Longhorn Display Driver Model (LDDM). Under the new display driver model, Microsoft wants to more closely integrate the graphics hardware with the operating system. In order to do this, a couple things are going to happen. First, graphics drivers will give up management of graphics memory to Windows. Windows will then handle the complete virtualization and management needs of graphics memory. This will have a large impact on the way graphics hardware vendors approach driver writing. In spite of the simplification windows memory management will bring to the graphics subsystem, different management techniques may lend themselves more readily to one hardware architecture or another. Right now, we are hearing that ATI and NVIDIA are both playing nice with Microsoft over what will happen when they lose the full control of their own RAM, but we will be sure to keep abreast of the situation.

In addition to the above issues with the LDDM (i.e. Windows sometimes has problems managing system RAM, and now they're going to manage VRAM?), Windows can't manage memory that is taken up by the video bios. There has been a push towards UEFI (Unified Extensible Firmware Interface) as a replacement to the archaic BIOS, and Microsoft would like to see the video BIOS become more entwined with the operating system. The plan right now is to make use of ACPI in order to facilitate this, but we may see even more advancements when we have UEFI hardware. Maintaining a higher level of integration on all fronts with the OS should help make more display options automatic and highly accessible.

Even if UEFI makes it into all hardware platforms by the end of 2006 and graphics hardware vendors take up the cause, we will still need to have legacy BIOS and VGA firmware support in all computers in order to run older (i.e. non-Longhorn) Operating Systems. AMD likens this transition to the current x86-64 transition. Hardware will support legacy and advanced functionality for some time until the user install base is such that legacy support can be dropped.

More On Longhorn Hybrid Hard Drives
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  • PrinceGaz - Tuesday, April 26, 2005 - link

    from page 3 "...and with the largest readily available DIMMs currently coming in at 2 GB in size"

    in reply to #5, #6 - Crucial have had 4GB PC2100 DIMMs available for purchase from their website for quite some time. They're certainly not cheap, but they are readily available. If you've got the cash I'm sure they'll sell you a few dozen of them.
  • DerekWilson - Tuesday, April 26, 2005 - link

    MS may have needed to restrict 64bit to long longs due to some internal operating system code issues ... If, in fact, linux distros that run on x86-64 impliment 64bit longs this may be the case. Otherwise I'd lean towards a hardware issue.

    At this point I haven't looked into it, but I will be sure to ask around (as this is surely the place to do it).
  • bobsmith1492 - Tuesday, April 26, 2005 - link

    Melgross - is that English?? I read it over real quickly and it was like... dude, what's he talking about? It just took a good close look though. :P
  • melgross - Tuesday, April 26, 2005 - link

    MS wants to control whatever they can. Control graphics memory and we are another step towards commoditized graphics boards.

    I wonder why MS went the way they did with the 64 bitness of the system. They went to (LL)P64 where just the long longs and the pointers are 64 bit, rather than LP64, where the longs are also 64 bit.

    They are the only ones to do that. It seems like a half measure. A conversion from any Unix distro (or OS X) would need more work than is good, as well as a lessening in it's effectiveness as a 64 bit system. Are the 64 bit extentions of the x86 chips at fault?
  • JarredWalton - Tuesday, April 26, 2005 - link

    Okay, the typos are fixed, and those that didn't like the 8-bit PNG graphics should now be happy. Iit was 4:30 AM when we finished, so our judgement was a bit impaired.) Just don't complain about how the PNGs are now five times as large. :)

    My personal opinion is that Windows XP removed most of the problems with the Windows platform. We'll see how Longhorn works out when it gets here, but that's still almost two years off. The graphics effects are nice, but pretty much totally unnecessary. Hopefully, we'll see some true improvements in the overall performance and not just eye candy.
  • Googer - Tuesday, April 26, 2005 - link

    Linux on a MAC: Total freedom from with in a confined space.
  • DerekWilson - Tuesday, April 26, 2005 - link

    tbh, with the current state of things Linux game performance is not up to par with windows. Even with windows managing graphics memory, windows performance will likely be better.

    And from a workstation perspective, having virtualized graphics memory for free is more of a blessing than a curse.

    I do think it would be better if MS gave graphics developers a choice whether to allow windows to manage graphics memory or not...
  • Son of a N00b - Tuesday, April 26, 2005 - link

    dont you dare go screwing up the performance of my vid card ms...if you do im going linux...
  • suryad - Tuesday, April 26, 2005 - link

    Agreed. Windows should not be managing graphics ram...unless MS came up with some new techniques...MS seems to be pulling out all the stops though in my opinion. I think the hybrid drive is a good idea but like #12 said...that is quite a concern!
  • Cygni - Tuesday, April 26, 2005 - link

    #10's post makes me giggle.

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