Anders Johansson wrote:
On Sunday 11 June 2006 22:06, James Knott wrote:
PAE is not virtual memory. Virtual memory is a method of making disk space appear as memory.
In general, virtual memory is a way of mapping one set of memory segments onto another memory segment. It's not inherent in the definition that it has to do with swap space, although that is a common use for it. But you can use a linux system without swap, and you'd still be using virtual memory. In particular, each application would still see its own contiguous memory space, even though it could be using non-contiguous chunks of real, physical memory
PAE is a memory mapping technique, that allows an applcation to access memory (real or virtual) beyond the normal 4 GB limit.
It looks to me like a variation of the standard Intel segmentation thing
Quite so. Back in the 8088 & 8086 days, the CPU had to use segment registers, to go beyond 64K bytes. The old DOS com files were an example of apps that couldn't go beyond 64K, because they didn't use the segment registers. The exe programs could use them to access the entire 1 MB range of the CPU. However, the applications had to "know" about using the segment registers, to access various areas of that 1 MB. Using the segment registers imposed a performance penalty. And again, only 64 K could be accessible at any time, for each of the 4 segment registers. -- Check the headers for your unsubscription address For additional commands send e-mail to suse-linux-e-help@suse.com Also check the archives at http://lists.suse.com Please read the FAQs: suse-linux-e-faq@suse.com