Re: perspectives on 32 bit vs 64 bit
Goswin von Brederlow wrote:
Intel has some extension that allows to address up to 64GB ram and
linux supports that.
Yes, PAE, for 64 GiB of physical, not /virtual/ RAM. Helege was trying
to suggest you can get 48-bits of virtual addressing space, which isn't
possible.
In PAE, 32-bit virtual addresses are translated to 36-bit physical ones.
The process still only sees 32-bit of space (and can only use 3G) but
that memory could physically be located anywhere in a 64GB range now,
instead of a 4G one.
But I'm not sure if that is also supported in
32bit mode on em64t. Wouldn't think so.
You mean, before entering long mode, or when running 32-bit apps in long
mode. The answers I beleive are yes and no, respectively.
Adam
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