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In computer operating systems, memory paging is a memory management scheme that eliminates the need for contiguous memory allocation. [1]It is often combined with the related technique of allocating and freeing page frames and storing pages on and retrieving them from secondary storage [a] in order to allow the aggregate size of the address spaces to exceed the physical memory of the system. [2]
Similarly, a page frame is the smallest fixed-length contiguous block of physical memory into which memory pages are mapped by the operating system. [ 1 ] [ 2 ] [ 3 ] A transfer of pages between main memory and an auxiliary store, such as a hard disk drive , is referred to as paging or swapping.
This is composed of main memory (RAM) and disk (pagefiles). The corresponding performance counter is called "Committed Bytes". Limit is the maximum possible value for Total ; it is the sum of the current pagefile size plus the physical memory available for pageable contents (this excludes RAM that is assigned to non-pageable areas).
In the x86 assembly language, the TEST instruction performs a bitwise AND on two operands. The flags SF, ZF, PF are modified while the numerical result of the AND is discarded. The OF and CF flags are set to 0, while AF flag is undefined. There are 9 different opcodes for the TEST instruction depending on the type and size of the operands. It ...
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.
In computing, mmap(2) is a POSIX-compliant Unix system call that maps files or devices into memory. It is a method of memory-mapped file I/O. It implements demand paging because file contents are not immediately read from disk and initially use no physical RAM at all.
MemTest86 and Memtest86+ are memory test software programs designed to test and stress test an x86 architecture computer's random-access memory (RAM) for errors, by writing test patterns to most memory addresses, reading back the data, and comparing for errors. [6]
However, QEMM maximum RAM is a shared 256MB XMS/256MB EMS, which is less than what DOS 7.10 and Windows 95/98 support without QEMM. MS-DOS 7.10 provides 624K free conventional memory and up to 1GB XMS/32MB EMS; assuming unaltered MS-DOS, using HIMEM.SYS and EMM386.EXE without any 3rd party utilities.