If 32-bit processor support is disabled in Windows Server 2008 R2, how does the operating system run 32-bit programs?
2 Answers
x64 CPUs can actually run 32-bit (x86) code in parallel to 64-bit code. The WOW64 layer of Windows translates the system calls of 32-bit programs to the 64-bit system routines.
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For more info, see en.wikipedia.org/wiki/WoW64. WOW64 does a good deal more than just translating 32-bit instructions into 64-bit ones; it's a very large and complex compatibility layer that interacts with a lot of different parts of the OS.– Zac BSep 30, 2012 at 17:21
The lack of 32-bit processor support simply means that Server 2008 R2 will not ship with a 32-bit edition, which means it requires a 64-bit processor to run.
It still runs 32-bit applications through the WOW64 compatibility layer.