Got Vista x64 questions? I've got answers
link: original article - section: windows
I got a lot of great questions and comments via e-mail and in the Talkback section of my previous post on the sudden surge in adoption rates for Windows Vista x64. In this follow-up, I summarize the answers I’ve found for each question.
I got a lot of great questions and comments via e-mail and in the Talkback section of my previous post on the sudden surge in adoption rates for Windows Vista x64. In this follow-up, I summarize the answers I’ve found for each question.
Rather than try to explain that here, I’m going to refer you to a very crisply written blog post by Microsoft’s Mark Russinovich, entitled “Pushing the Limits of Windows: Physical Memory.” The short version is that 32-bit operating systems can, in theory, address memory above the 4GB line on specially configured systems, but doing so is problematic:
[When] Windows XP SP2 was under development, client systems with more than 4GB were foreseeable, so the Windows team started broadly testing Windows XP on systems with more than 4GB of memory. […]
What they found was that many of the systems would crash, hang, or become unbootable because some device drivers, commonly those for video and audio devices that are found typically on clients but not servers, were not programmed to expect physical addresses larger than 4GB. As a result, the drivers truncated such addresses, resulting in memory corruptions and corruption side effects. Server systems commonly have more generic devices and with simpler and more stable drivers, and therefore hadn’t generally surfaced these problems. The problematic client driver ecosystem [led] to the decision for client SKUs to ignore physical memory that resides above 4GB, even though they can theoretically address it.
