Windows on Windows

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Windows on Windows

Windows software that runs applications written for previous versions of Windows. Included in 32-bit versions of Windows, Windows on Windows 16 (WoW16) emulates the Windows 3.x operating system kernel and enables 16-bit Windows 3.1 apps to run. See NTVDM.

WoW64
Included in 64-bit versions of Windows, Windows on Windows 64 creates a 32-bit environment that allows 32-bit apps to run. WoW64 handles the discrepancies between 32-bit and 64-bit versions of the Registry. It also allows a 32-bit app to use a full 4GB of virtual memory, which is more than it would have in 32-bit Windows. When running in 32-bit Windows, some of that address space is used by Windows itself. See binary values.
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References in periodicals archive ?
Applications running on x64 should theoretically experience improved performance because of the larger quantity of available memory, even if the application is running within the WoW64 layer.
This emulation layer, known as Windows on Windows 64 or WOW64, enables 32-bit programs to run as though on a 32-bit version of Windows.