Win16 on Win32 (WOW) environment
Win16 on Win 32 WOW
The key mode for backward compatibility in a Windows 32-bit environment is the Windows on Windows 64 (WoW64) subsystem. WoW64 allows 32-bit applications to run seamlessly on 64-bit versions of Windows by providing a compatibility layer that translates 32-bit calls to 64-bit operations. This ensures that legacy 32-bit applications can function without modification on modern 64-bit Windows systems.
The Win32 subsystem is the native environment of Windows 2000. It processes all 32-bit applications. It provides text window support, shutdown, and hard-error handling for all subsystems. Applications created for Windows NT, Windows 95, and Windows 98 are also run on the Win32 subsystem.
To use 64-bit specific applications, you must purchase both a 64-bit processor and a 64-bit version of Windows. 64-bit applications will not run on 32-bit versions of Windows, even if a 64-bit capable processor is installed. You also cannot install a 64-bit version of Windows on a 32-bit only processor.
Yes.
Windows XP Professional x64 Edition
Microsoft Windows XP 64 Bit Edition ?
C:\Program Files (x86)\ is the default folder for 32-bit applications on 64-bit Windows.
Only Windows 64-bit operating systems can run 64-bit applications
The Win32 folder, often referred to as the "Windows System32" directory, is generally located at C:\Windows\System32 on Windows operating systems. This folder contains essential system files and libraries necessary for the operation of Windows and its applications. In 64-bit versions of Windows, there is also a C:\Windows\SysWOW64 folder, which contains 32-bit applications and files.
No special action is needed. 32-bit applications are run transparently.
I doubt there's any way to really quantify "worst." Windows NT running on non-Intel architectures could only run certain MS-DOS programs under emulation, and 64-bit versions Windows XP/Vista/7 cannot run 16-bit applications at all. 32-bit versions of Windows Vista and 7 can run 16-bit Windows applications, but MS-DOS programs are limited to text mode.