Hi Tim,

Yes, this is how x64 Windows works.

WOW64, short for "Windows-32-on-Windows-64," is responsible for providing two levels of support for 32-bit legacy applications. WOW64 prevents file and registry collisions between 32-bit and 64-bit versions of applications by redirecting the 32-bit registry and file system accesses.

SetupBuilder Developer Edition lets you create native 32-bit, hybrid 32/64-bit, or 64-bit enabled setup programs.

Although the WOW64 subsystem doesn't support every type of application, it does let Windows x64 run almost all 32-bit existing Windows applications. The types of applications that aren't supported are low-level applications such as antivirus programs or programs that attempt to directly access system hardware. The 32-bit applications that run in the WOW64 subsystem are executed at full speed. In fact, because of the larger data path the x64 architecture provides, many 32-bit applications will actually run faster in the WOW64 subsystem than they would on native 32-bit hardware.

The WOW64 subsystem isolates the execution of 32-bit applications from 64-bit applications.

First, the system files in Windows x64 Edition are not present on just the Windows\System32 folder, but split into two folders to separate the 32-bit applications from the 64-bit applications. The WOW64 subsystem intercepts calls from a 32-bit legacy application and redirects it to the Windows\SysWow64 folder. If the call is from a 64-bit application, then the call is routed to the Windows\System32 folder and does not involve the WOW64. Microsoft has retained the name System32 for the folder, which hosts the 64-bit system files. The "Program Files" folder on a x64 system which stores 32-bit legacy applications is named Program Files (x86). 64-bit applications are stored in the Program Files folder.

Second, the WOW64 subsystem also provides redirection at the Registry level. Computers that are running an Windows x64-based operating system use a different registry layout to handle both 32-bit and 64-bit programs. The registry layout changes in x64 Edition versions of the Windows operating system make sure that the programs hard-coded .dll paths, program settings, and other parameter values are not overwritten. If the call is from a 32-bit application, then the call to access the HKLM\Software registry hive is intercepted by the WOW64 subsystem and redirected to the HKLM\Software\Wow6432Node. If the call is from a 64-bit application, then it is routed to the HKLM\ Software node.

Registry Redirection

To prevent 32-bit registry settings from overwriting the 64-bit registry settings, computers that are running an x64-based version of Windows store the settings for 32-bit programs in a new branch in the registry.

32-bit programs and 64-bit programs that are running on an x64-based version of Windows operate in different modes and use the following sections in the registry:

Native mode 64-bit programs run in Native mode and access keys and values that are stored in the following registry sub key:

HKEY_LOCAL_MACHINE\Software

32-bit programs run in WOW64 mode and access keys and values that are stored in the following registry sub key:

HKEY_LOCAL_MACHINE\Software\WOW6432node

This redirection lets you maintain separate configurations for 32-bit and 64-bit processes. 64-bit programs see the 64-bit version of the registry, while 32-bit programs see the 32-bit version.

File System Redirection

All 32-bit file access to the %systemroot%\system32 folder is redirected to the %systemroot%\syswow64 folder (the %systemroot%\syswow64 that contains a copy of 32-bit Windows system executable programs). This redirection lets a 32-bit applications load the correct 32-bit system executables rather than attempting to access the 64-bit OS executable programs.

Does this help?

Friedrich