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(For 32-bit and 64-bit versions of Windows, inter-process sharing occurs only where different executables load a module from exactly the same directory; the code but not the stack is shared between processes through a process called "memory mapping".) Thus, even when the desired DLL is located in a directory where it can be expected to be found ...
Each user space process normally runs in its own virtual memory space, and, unless explicitly allowed, cannot access the memory of other processes. This is the basis for memory protection in today's mainstream operating systems, and a building block for privilege separation .
It also uses the topmost bit of the 64-bit page table entry as a no-execute or "NX" bit, indicating that code cannot be executed from the associated page. The NX feature is also available in protected mode when these CPUs are running a 32-bit operating system, provided that the operating system enables PAE.
The Linux kernel supports the NX bit on x86-64 and IA-32 processors that support it, such as modern 64-bit processors made by AMD, Intel, Transmeta and VIA. The support for this feature in the 64-bit mode on x86-64 CPUs was added in 2004 by Andi Kleen, and later the same year, Ingo Molnár added support for it in 32-bit mode on 64-bit CPUs.
In computing on Microsoft platforms, WoW64 (Windows 32-bit on Windows 64-bit) is a subsystem of the Windows operating system capable of running 32-bit applications on 64-bit Windows. [1] It is included in all 64-bit versions of Windows, except in Windows Server Server Core where it is an optional component, and Windows Nano Server where it is ...
A modern x86 CPU may use more than 4 GB of memory, either utilizing the native 64-bit mode of x86-64 CPU, or the Physical Address Extension (PAE), a 36-bit addressing mode. In such a case, a device using DMA with a 32-bit address bus is unable to address memory above the 4 GB line.
These instructions are also available in 32-bit mode, in which they operate on 32-bit registers (eax, ebx, etc.) and values instead of their 16-bit (ax, bx, etc.) counterparts. The updated instruction set is grouped according to architecture ( i186 , i286 , i386 , i486 , i586 / i686 ) and is referred to as (32-bit) x86 and (64-bit) x86-64 (also ...
In computing, protected mode, also called protected virtual address mode, [1] is an operational mode of x86-compatible central processing units (CPUs). It allows system software to use features such as segmentation, virtual memory, paging and safe multi-tasking designed to increase an operating system's control over application software.