"R. C. White" wrote in message
...

John is correct, but, since many more users are now seeing 64-bit
Windows for the first time, a fuller explanation might be in order.

Those TWO folders are in all 64-bit Windows versions. They are NOT in
32-bit Win7 or other 32-bit Windows. They were introduced in Windows
XP x64, and also appear in Vista x64 and Windows 7 x64.

We've had the Program Files folder since Windows 9x, of course, long
before 64-bit Windows first appeared. There was no thought of 64-bit
applications until WinXP x64. But when 64-bit Windows arrived, there
was a need to separate 64-bit operations and applications from 32-bit.
Differences in the operating system itself were handled by creating
separate editions of the OS: Windows XP Professional continued as
32-bit, and Window XP x64 was introduced almost as a
"behind-the-curtain" product that never appeared as a retail package.
But it established some patterns that have continued in 64-bit Vista
and Win7.

To keep 32-bit and 64-bit apps separate in Win64 (my collective term
for all 64-bit versions of Windows), MSFT could have created a new
"Program Files (x64)" folder and left 32-bit apps in the familiar
"Program Files". But they did not. Instead, they decided that Win64
would use "Program Files" for 64-bit apps only; 32-bit apps in Win64
would go into the newly-created "Program Files (x86)".

That decision created the confusion that has existed ever since WinXP
x64 but never got much attention until Windows 7.
Almost all new computers are using CPUs and other hardware that are
64-bit capable, and many (most?) new computers are being delivered
with 64-bit Windows 7 installed. So many more users are becoming
aware of "Program Files (x86)" for the first time - and are asking the
question that you have posted.

When I first encountered PF86 (my abbreviation) in WinXP x64 in about
2005, I assumed that it was for 64-bit apps, since it existed only in
64-bit Windows. It took me several months to realize that the "x86"
label derived from the "x86" line of Intel 32-bit CPUs (8086, 80286,
80486, etc.) and applied to 32-bit Windows and apps, not 64-bit. By
that time, I had hopelessly jumbled my 32-bit and 64-bit apps in my PF
and PF86 folders.

So I certainly understand your confusion, Dabbler, and I'm sure that
it is widespread among users who are having their first introduction
to 64-bit Windows with their new Win7 x64 computers.

The reason for separating 32-bit apps from 64-bit versions is not just
cosmetic. I'm not a techie, so I can't give a technical explanation.
But my understanding is that 64-bit apps require different supporting
files, such as DLLs and drivers, and that 32-bit apps on Win64 need to
use a "transition layer" called WOW (Windows on Windows). Having the
app files separated by "bitness" into different PF folders allows
Win64 to know which supporting services to use for each version of
each app.

One example of all this is Internet Explorer. Win7 x64 comes with TWO
versions of IE8 installed; 32-bit Win7 has only the 32-bit version.
In Win7 x64, you will find the two versions at:
32-bit version: C:\Program Files (x86)\Internet Explorer\iexplore.exe
64-bit version: C:\Program Files\Internet Explorer\iexplore.exe

When you click the big blue "e", the 32-bit version of IE8 runs, by
default. You can run the 64-bit version by browsing to it in the PF
folder, as usual for any application. Or, like any other app, you can
create a shortcut or an icon or pin it to your Taskbar, etc. The two
versions perform ALMOST identically. But, for example, Adobe Flash
Player will not run in the 64-bit IE8 because Adobe has not yet
updated Flash for 64-bit. Flash will run in 32-bit IE8 on Win64. (To
see which version of IE you are currently running, click Help | About
Internet Explorer; the 32-bit edition does not mention "bitness", but
the 64-bit Edition says "64-bit Edition" on the Version line. And,
yes, you can have both versions open at the same time.)

I hope this helps others who may be "reading over our shoulders". In
a newsgroup, "lurking" is A Good Thing. ;)

Thanks for the historical background for naming those two PF files.
Though I did not mention I was running the 64-bit version of W7, I
thought it was implied by the occurance of those two PF folders. To me
it kinda' makes sense that in a 64-bit version they use the X86 suffix
for 32-bit programs when I view it this way: use the plain "Program
Files" for those programs that are built with the OS bit size; 32-bit
programs for 32-bit OS, 64-bit programs for 64-bit OS. Thus, using the
x86 suffix makes sense for PF folder name where programs are installed
that are not native for that OS. This also explains why there was no
need for two different PF folders for 32-bit OS's, except when they
could have run 16-bit programs. But I don't remember how 32-bit OS's
handled 16-bit programs. Do you?