4 ms·
I'm not sure if this is the right answer or not, but the Linux kernel has supported PAE[1] for ages, which allows for more than 4GB of RAM in a 32-bit OS (thoug
by rmk2 14y ago
I'm not sure if this is the right answer or not, but the Linux kernel has supported PAE[1] for ages, which allows for more than 4GB of RAM in a 32-bit OS (though it remains unusable by a single process, if I understood that correctly). Maybe someone else with a better understanding of the 32bit/64bit differences can chime in.
[1]: https://en.wikipedia.org/wiki/Physical_Address_Extension https://en.wikipedia.org/wiki/Physical_Address_Extension
- kbolino 14y agoPAE would definitely enable them to use all 32GBs of physical memory. Both Windows and Linux have PAE support, but non-server editions of Windows still limit the physical address space to 4GB (although this might seem to make PAE support pointless, there are other advantages of PAE, like the NX/XD bit used for DEP). You are also correct that the per-process limit of 4GB of virtual memory is not affected by PAE. In case the advantages of PAE once again seem pointless, remember that a system can execute multiple 32-bit programs each with its own independent address space, so you can have, in theory, eight programs each using its own 4GB on a 32GB system without running out of memory. In practice, the platform imposes a limit of <4GB for physical memory, with the remainder used for legacy support and hardware DMA. Also, the operating system imposes a limit of <4GB for virtual memory, with the remainder used by the kernel.