I mentioned a couple of weeks ago that applications certified to run on Windows Vista must run on x64 as well as 32-bit Vista. Wow64 makes this easy for most 32-bit Windows applications: they automatically run in a 32-bit compatibility environment and never know the difference unless they check the IsWow64Process API. I said then that a tester had found that merely running certain applications would screw u I mentioned a couple of weeks ago that applications certified to run on Windows Vista must run on x64 as well as 32-bit Vista. Wow64 makes this easy for most 32-bit Windows applications: they automatically run in a 32-bit compatibility environment and never know the difference unless they check the IsWow64Process API.I said then that a tester had found that merely running certain applications would screw up the keyboard and mouse on Vista for x64. This report turned out to be irreproducible: as far as we can tell, it was a matter of a bad driver installation for a wireless mouse and keyboard. When I tried the same application on a laptop with Vista for x64 installed, I couldn’t make the problem happen. When the tester scrubbed his system and reinstalled everything from scratch, the problem went away.Testing the application on 64-bit Vista made it clear that Wow64 is not an unalloyed blessing. For a system utility, the sandboxes drastically reduce what the program can do. A 32-bit program scanning the 64-bit registry can only see the registry hives under Wow6432Node. A 32-bit program scanning for running programs can only see itself and any other 32-bit programs running in the Wow64 environment. Next week I’m probably going to have to build a 64-bit version of this C++ application. Based on what I went through 15 years ago making 16-bit Windows programs work on 32-bit Windows, I’m not looking forward to the exercise. Software Development