Messages in this thread | | | From | "Stephen C. Tweedie" <> | Date | Thu, 19 Aug 1999 17:49:11 +0100 (BST) | Subject | Re: [bigmem-patch] 4GB with Linux on IA32 |
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Hi,
On Thu, 19 Aug 1999 13:33:32 +0000, Thierry Vignaud <tvignaud@mandrakesoft.com> said:
> since only recent motherboard support more than 512Mb RAM, and since > they used i686 (PPro, P2, P3), why not use the pse36 extension of > these cpu that enable to stock the segment length on 24bits, which > give 64To when mem unit is 4b page. this'll make the limit much > higher (say 128Mb RAM for the kernel space memory and 15,9To for the > user space).
The PAE36 extensions let you address 64GB of physical memory, but don't change the fact that you still have a 32-bit user address space: the user space is still limited to 3GB.
> This would break some api, but why not add foo_64 for each foo() > function as glibc does for big files ? As for standard api such as of > libc, i don't think wa have to worry about. There are few Programs > which want a lot of memory such as oracle. For these, we may find a > special way of accessing the mem (64bits pointers, 64bit mmap, ...)
The CPU doesn't support 64 bit pointers. Kind of makes it a bit inefficient to access the user memory if you have to make a system call every time. :)
--Stephen
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