Tzvetan Mikov (tzvetanmi@yahoo.com) on 5/13/07 wrote:
---------------------------
>Linus Torvalds on 5/13/07 wrote:
>---------------------------
>>[...]So no, PAE does not mean that you can use more than
>>4GB of RAM. Even before PAE, the practical limit was around
>>1GB, and PAE didn't move that post a fraction of an inch!
>
>Can you please elaborate on the practical 1 GB limit a little further ?
>
>(Lets leave PAE aside - I think you are being too harsh on the hw designers; I
>doubt that any engineer ever thought PAE was anything more than a temporary hack,
>as was HIMEM actually, but it was probably much easier/cheaper than designing a
>64-bit CPU. What marketing did with that is another story ...)

Well, IMHO, Intel simply didn't want to release a
64bit extension to x86 because they wanted to maintain
segmentation between IA64 and x86... so PAE was a
handy kludge they could point to for the growing fraction
of users with larger memory needs.


>Do you mean that it is absolutely impossible for a 32-bit OS to efficiently use
>RAM > 1 GB, or that it complicates the kernel compared to a hypothetical scenario
>with the same amount of RAM and 64-bits ?

Well, I think he's trying to say after that you have to
start making serious performance tradeoffs...(I should
probably just shut up and let him answer)