windows中，有關2G memory的限制

http://www.brianmadden.com/content/content.asp?ID=69

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore/html/vcreflargeaddressaware.asp

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/memory/base/address_windowing_extensions.asp