Search results
Results from the WOW.Com Content Network
The Windows Task Manager utility for Windows XP and Server 2003, in its Performance tab, shows three counters related to commit charge: Total is the amount of pagefile-backed virtual address space in use, i.e., the current commit charge. This is composed of main memory (RAM) and disk (pagefiles).
EMM386.EXE can map memory into unused blocks in the upper memory area (UMA), allowing device drivers and terminate-and-stay-resident programs to be "loaded high", preserving conventional memory. The technique probably first appeared with the development of CEMM , included with Compaq's OEM MS-DOS for the Compaq Deskpro 386 in 1986.
Virtual memory in the 8088 and 8086 was not supported by the processor hardware, and disk technology of the time would make it too slow and cumbersome to be practical. Expanded memory was a system that allowed application programs to access more RAM than directly visible to the processor's address space. The process was a form of bank switching.
Guide On Optimizing Virtual Memory Speed (outdated) Virtual Memory Page Replacement Algorithms; Windows XP: How to manually change the size of the virtual memory paging file; Windows XP: Factors that may deplete the supply of paged pool memory; SwapFs driver that can be used to save the paging file of Windows on a swap partition of Linux
Windows XP supports a larger system virtual address space—1.3 GB—of which the contiguous virtual address space that can be used by device drivers is 960 MB. The Windows XP Memory Manager is redesigned to consume less paged pool, allowing for more caching and greater availability of paged pool for any component that needs it.
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 DOS machines can operate either exclusively through typical software emulation methods (e.g. dynamic recompilation) or can rely on the virtual 8086 mode of the Intel 80386 processor, which allows real mode 8086 software to run in a controlled environment by catching all operations which involve accessing protected hardware and forwarding them to the normal operating system (as exceptions).
This means that 48 bits of virtual page number are translated, giving a virtual address space of up to 256 TB. For some processors, a mode can be enabled with a fifth table, the 512-entry page-map level 5 table ; this means that 57 bits of virtual page number are translated, giving a virtual address space of up to 128 PB.