What is syswow64 folder?

Wow64 (Windows-on-Windows 64-bit) is a subsystem of the Windows operating system that can run 32-bit applications, and exists in all 64-bit versions of Windows-including

• Windows 2000 limited edition
• Windows XP Professional x64 Edition, and IA-64
• 64-bit Windows Server 2003
• 64-bit Windows Vista
• 64-bit Windows Server 2008
• 64-bit Windows 7

On Windows Server 2008 R2, this is an optional component. wow64 is designed to handle many differences between 32-bit windows and 64-bit windows, especially the differences in the structure changes of windows.

 

Conversion Library

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Wow64 sub-system is a lightweight compatibility layer, which has the same interface in all versions of Windows. it is mainly used to create a 32-bit environment, so that 32-bit applications can run on 64-bit systems without any modification, it provides required interfaces.

Technically, wow64 is implemented by three DLL.

• Wow64.dllIs the core interface of Windows NT kernel. It is converted between 32-bit and 64-bit calls, including pointer and call stack control.
• Wow64win. dll provides a proper entry pointer for 32-bit applications.
• Wow64cpu.dllConverts the processor between 32-bit and 64-bit modes.

Registry and File System

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The Wow subsystem also handles other key aspects of running 64-bit applications. for example, when you manage the interaction between a 32-bit application and the Windows Registry, an interface is provided to the storage subsystem (the 32-bit registry is different from the 64-bit registry .)

Operating system usage% SystemRoot % \ system32 directory to store 64-bit library files and executable files. this is intended for backward compatibility, because many applications in the old system use the hardcoded method to obtain this path. when a 32-bit application is executed, wow64 redirects the DLL request from system32% SystemRoot % \ syswow64Contains the library and executable files of the old system in the syswow64 directory.

 

From:

Wikipedia-wow64

Http://en.wikipedia.org/wiki/WoW64