Search results
Results From The WOW.Com Content Network
4-level paging of the 64-bit mode. In the 4-level paging scheme (previously known as IA-32e paging), the 64-bit virtual memory address is divided into five parts. The lowest 12 bits contain the offset within the 4 KiB memory page, and the following 36 bits are evenly divided between the four 9 bit descriptors, each linking to a 64-bit page table entry in a 512-entry page table for each of the ...
The required disk space may be easily allocated on systems with more recent specifications (i.e. a system with 3 GB of memory having a 6 GB fixed-size page file on a 750 GB disk drive, or a system with 6 GB of memory and a 16 GB fixed-size page file and 2 TB of disk space).
The entries in the page directory have an additional flag in bit 7, named PS (for page size). If the system has set this bit to 1, the page directory entry does not point to a page table but to a single, large 4 MB page (Page Size Extension).
Some instruction set architectures can support multiple page sizes, including pages significantly larger than the standard page size. The available page sizes depend on the instruction set architecture, processor type, and operating (addressing) mode. The operating system selects one or more sizes from the sizes supported by the architecture.
In this case the page is paged out to a secondary store located on a medium such as a hard disk drive (this secondary store, or "backing store", is often called a swap partition if it is a disk partition, or a swap file, swapfile or page file if it is a file). When this happens the page needs to be taken from disk and put back into physical memory.
This occurs when a program requests a block of memory that does not cleanly map into a page, for instance, if a program requests a 1 KB buffer to perform file work. In this case, the request results in an entire page being set aside even though only 1 KB of the page will ever be used; if pages are larger than 1 KB, the remainder of the page is ...
The entries in the page directory have an additional flag, in bit 7, named PS (for page size). This flag was ignored without PSE, but now, the page-directory entry with PS set to 1 does not point to a page table, but to a single large 4 MiB page. The page-directory entry with PS set to 0 behaves as without PSE.
Page Size Extension: If set, enables 32-bit paging mode to use 4 MiB huge pages in addition to 4 KiB pages. If PAE is enabled or the processor is in x86-64 long mode this bit is ignored. [14] 5: PAE: Physical Address Extension: If set, changes page table layout to translate 32-bit virtual addresses into extended 36-bit physical addresses. 6: MCE