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Energy Efficiency and Windows Mobile PCs
We've been working on battery life performance issues with system manufacturers and driver developers. Windows Vista Service Pack 1 (SP1) will provide some advances that you can take advantage of in designing and testing systems and devices. Just a few ideas: Design and test systems with aggressive power efficiency settings in system power policies. We provide extensive design and testing guidance in the white papers listed on the new Battery Life and Energy Efficiency WHDC page. Design and test WDDM drivers by using the new VSync Control in Windows Vista SP1. Newer processors and platforms provide opportunities for Windows to conserve energy when the computer system is idle. However, periodic system activity such as firing of interrupts can result in peak power usage and can prevent the PC from entering transient sleep states to conserve energy.
Beginning with Windows Vista SP1, Windows can turn off periodic VSync interrupt counting (that is, the monitor refresh rate) when the screen is not being refreshed from new graphics or mouse activity. Controlling the VSync interrupt interval can result in significant energy savings. Find out about driver and registry changes in this new article on WHDC. Configure and test DVD playback performance and Windows Vista with new defaults. By default, the Windows DVD playback stack renders 60-fields-per-second interlaced DVD content at a rate of 60 frames per second. When you are preconfiguring mobile PCs with Windows Vista SP1, you can set the default playback rate to 30 frames per second for interlaced content when the mobile PC is running on battery. This has been shown to result in significant energy savings. System manufacturers will find guidelines and settings in the addendum information for the Windows OEM Preinstallation Kit.
In previous newsletters, we've discussed Windows Disk Idle Detection and the opportunities for system manufacturers to configure power policies to spin down hard disk drivers to reduce power consumption. We've also discussed tips and tricks for Measuring Performances in Windows Vista to ensure that your system and device tests are accurate and repeatable--very important when you're trying to determine the power efficiency gains in driver, hardware, and policy changes for PC preinstallation images and for retail hardware packages.
Please include "power efficiency" and "battery life" in your design and integration testing for hardware that works with Windows Vista SP1. To learn more about the current Release Candidate and details for this release, see the Windows Vista Developer Center on MSDN.
-- The WHDC Web team
WHDC After Dark: Our Top 5 Picks for 2007 From the Editor: After this edition, a new editor will be taking over the Microsoft Hardware Newsletter. It's a good moment for looking back--except I'm only going to look at 2007, though I've been involved with this newsletter since 1997. Here are my top picks on the WHDC Web site for 2007: 5. Removing Support for Industry Standard Architecture (ISA) Bus--Perhaps you thought this was a snoozer of a topic, but we invented the Microsoft Hardware Newsletter in the mid-90s when the PC industry was working to get devices off ISA and onto PCI. Favorite tip: Follow industry specifications precisely in your hardware registers. Your customers will be grateful (though your solution will be transparent to them, because your device just works). 4. Advances in Memory Management for Windows--This paper takes a deep look into major enhancements in Windows Vista and Windows Server 2008. Favorite tips for hardware manufacturers: Use ECC. For driver developers: Never attempt to access memory beyond what the driver has allocated. (Driver Verifier is your best friend.) 3. Performance Tuning for Windows Server 2008--When we tell you that boot environment, I/O manager, and memory manager for Windows has completely changed, then you next want details about registry settings and tuning parameters, right? The Performance team delivers the details. Favorite basic tips: "Choose 64-bit processors due to the benefit of additional address space. Match and scale the memory and I/O subsystem with the CPU power." 2. Designing Power-Friendly Devices--This WinHEC paper from Barnes Cooper et al. at Intel Corporation goes far beyond "re-use your shopping bag" to address Green goals. Power efficiency in PCs and servers requires a major effort in the industry through the coming decade. Get a jump on the tasks ahead by understanding the key design issues, especially for PCI Express 2.0 and USB 2.0. Favorite tip: "For USB 2.0, proper use of traffic classes, improved use of selective suspend, and proper idle detection through applications and end-user-visible buttons can reduce power significantly without affecting performance." My top pick: 1. [ with a bullet] Developing Drivers with Windows Driver Foundation from MS Press--OK, I'm prejudiced because my team wrote this. But in fact, it's the top pick because it's a direct representation of the driver design and development guidelines straight from the Windows Driver team in the Windows Device Platform Group. If your device works with Windows, or if your application has to talk to hardware, you absolutely need this book.
Best wishes for 2008: Design smart, code smart, test smart--and look for power efficiencies everywhere.
— Annie Pearson, Microsoft Hardware News editor, WHDC
Developing and Testing for Windows Server 2008 and Windows Vista SP1
Windows Logo Program Tools and News
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On MS Connect, look for "Microsoft Windows Driver Kit (WDK) and Windows Logo Kit (WLK)" in the "Available Connections" list. This kit can be used for all current logo programs. Submissions for Windows Server 2008 and Windows Vista SP1 must use WLK 1.1.
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