Search results
Results From The WOW.Com Content Network
How Virtual Memory Works from HowStuffWorks.com (in fact explains only swapping concept, and not virtual memory concept) Linux swap space management (outdated, as the author admits) Guide On Optimizing Virtual Memory Speed (outdated) Virtual Memory Page Replacement Algorithms; Windows XP: How to manually change the size of the virtual memory ...
A page, memory page, or virtual page is a fixed-length contiguous block of virtual memory, described by a single entry in a page table.It is the smallest unit of data for memory management in an operating system that uses virtual memory.
It will also change when already-running programs allocate or free private virtual memory; for example, with the VirtualAlloc and VirtualFree APIs. In the Task Manager utility under Windows XP and Windows Server 2003 , the graphical displays labeled as "PF usage" and "Page File Usage History," despite their labels, reflect not the pagefile ...
A similar mechanism is used for memory-mapped files, which are mapped to virtual memory and loaded to physical memory on demand. When physical memory is not full this is a simple operation; the page is written back into physical memory, the page table and TLB are updated, and the instruction is restarted.
By reducing the I/O activity caused by paging requests, virtual memory compression can produce overall performance improvements. The degree of performance improvement depends on a variety of factors, including the availability of any compression co-processors, spare bandwidth on the CPU, speed of the I/O channel, speed of the physical memory, and the compressibility of the physical memory ...
Virtual memory combines active RAM and inactive memory on DASD [a] to form a large range of contiguous addresses.. In computing, virtual memory, or virtual storage, [b] is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" [3] which "creates the illusion to users of a very large (main) memory".
With virtual memory, a contiguous range of virtual addresses can be mapped to several non-contiguous blocks of physical memory; this non-contiguous allocation is one of the benefits of paging. [8] [3] However, paged mapping causes another problem, internal fragmentation. This occurs when a program requests a block of memory that does not ...
Thrashing occurs when there are too many pages in memory, and each page refers to another page. Real memory reduces its capacity to contain all the pages, so it uses 'virtual memory'. When each page in execution demands that page that is not currently in real memory (RAM) it places some pages on virtual memory and adjusts the required page on RAM.