[geeks] Windows XP 64bit Licensing?

[nate at portents.com]

> What difference does that make?  Ugly, sure... but on a virtual address
> system like Linux does it matter?

http://www.codinghorror.com/blog/archives/000811.html

"To be perfectly clear, this isn't a Windows problem-- it's an x86
hardware problem. The memory hole is quite literally invisible to the CPU,
no matter what 32-bit operating system you choose."

> All memory in Linux is virtual addresses and any given physical address
> can be marked off limits for paging VM.

Really.  Then explain this:

http://ubuntuforums.org/showthread.php?t=484222

> What specific problem have you seen?

The one I've been describing that is specific to the x86 32-bit architecture.

And yes, there are ways around it with memory extentions such as 36-bit
PAE, which has it's own unique set of limitations and restrictions, here's
how you'd set up PAE in 32-bit Linux for Oracle:

http://www.oracle-base.com/articles/linux/LargeSGAOnLinux.php

> It doesn't mean you don't have access to all 4GB, it just means no single
> process can access more than 3GB.
>
> That's probably the model that Windows defaults to.

No, Windows defaults to a maximum address space of 2GB per application. 
And on top of that adding the /3GB switch to Windows' boot.ini file will
only enable a 3GB address space for applications which have been the bit
IMAGE_FILE_LARGE_ADDRESS_AWARE set in their image header.

- Nate