WoW - Windows on Windows | Windows 7 - 64 bit and 32 bit compatibility
A very rarely known feature of Windows which allows 32 bit applications to run on 64 bit operating systems. Hence, it frees the user from downloading additional version of same software.
Windows Vista was a jump from Windows XP, so much so that the users were not ready to accept that drastic change in the way things were going to work. While working of the system was one thing which changed, a lot more had changed as well. Windows Vista and Windows 7 come in packages which have DVDs instead of CDs and every package has got both the 32 bit and 64 bit DVDs so that if you want to have the taste of the faster machine which runs on 64 bit processor, a 64 bit Windows OS will help you to speed up things.
It's usually said that 64 bit processing makes sense only with a 64 bit OS and that is right! A 64 bit processor along with the 64 bit OS will work as much as 150% faster because it can process more data. but having a 64 bit Operating System has its own caveats. The biggest problem there is the availability of software. You would not like to select each and every software out there on the internet and then search for their 64 bit version. software like VLC media player, Firefox, Office packages etc are regularly distributed by the tech magazines and it would be a great headache if you had to download each and every software separately for the 64 bit version Windows.
Windows 64 bit edition comes with something called as a 'WoW' framework which allows you to run most of the 32 bit application made for Windows on the 64 bit OS. This WoW framework is also called as "Windows on Windows" which is also its expanded form for which it stands. The WoW which comes with Windows Vista and Windows 7 is called as "WoW 64" because it allows 32 bit programs to run natively on the '64' bit OS.
So if you were to install a 32 bit application on a 64 bit OS, Windows 7 would happily allow you to do that! However it would do it a bit differently! While the default folder in which the applications get installed is C:\Program Files, in this case, the installation folder becomes "C:\Program Files (x86)". The additional 'x86' written in the brackets signify that this folder contains the '32 bit' programs. It is to be noted that 'x86' is technically almost an standard to indicate the 32 bit version of the processors made by Intel. Windows will still maintain an additional folder named "C:\Program Files" which would hold the native 64 bit programs. This functionality again depends on the application. For example, while the 32 bit version of VLC media player has no objection or problem in getting installed on the 64 bit OS, iTunes music player from Apple asks you to download the 64 bit version of the player and then install it. Compatibility of Software
Compatibility of the operation or working of the software is a major issue which comes to mind in this case, as this is a special case. While there can be minor glitches with some applications, the WoW framework handles all things pretty well in most of the cases. The running application runs as it would have been on a 32 bit OS. People with some in-depth understanding would say that the instructions for 64 bit and 32 bit software are different and hence there is a major chance of incompatibility issue coming into the picture. While they are right, Microsoft had prepared the answer to it in the form of WoW. The work of WoW framework is exactly to solve this very problem. How WoW solves the problem is that when one starts an application, Windows determines to see whether that application is made for the platform which the OS is running on, or not. In this process, the 64 bit OS comes to know that the application which it is trying to run is a 32 bit program. On this, the Windows OS invokes (technical term for starts) the WoW framework and tells the framework to run the given application. The WoW framework consists of different DLL (Dynamic Link Library) files. The framework loads the 32 bit application to the RAM and when the application issues a request to the OS, the WoW framework takes those requests in 32 bit format and converts them to the 64 bit format which the rest of the system understands. When the system responds with the results of the requests made by the application, the WoW framework once again changes them back to the 32 bit format which the application will understand. This way, the application becomes compatible with the rest of the system which is running on 64 bit. It is to be known that WoW framework came with Windows first in Windows XP professional edition (64 bit), before Windows Vista came to market.
This rule too has its own exceptions. One of the biggest exceptions to the WoW interoperability is the DirectX applications, which are mainly games. Hence, while the 32 bit version games may work on the 64 bit version Windows, they may fail without any warning which is more irritating. In some cases, even the professional class applications such as Adobe creative suite (Photoshop, Dreamweaver, InDesign etc) crash when a 32 bit version is tried to run on a 64 bit OS. As a bottom line for the compatibility issue for applications would be - While Microsoft has tried its best to provide maximum compatibility for all sorts of 32 bit applications, it still fails at times due to the design of the applications themselves.Benefits of Windows on Windows
The first and the greatest benefit is that you don't have to bother about the application being 32 bit or 64 bit. In most of the cases, Windows will run it for you without any problems, even without letting you know that the application you are running is a 32 bit application.
Secondly, you can download and use the applications which do not have a 64 bit version available. This makes you feel at home. This is not the case with the Linux or other operating systems and hence is a big plus point for Windows. While other operating systems usually come with a compatibility framework like WoW framework, they usually fail to deliver the comfort and ease of use which WoW framework does.
Third, you can get the software from your friends and install it on your 64 bit PC without much worries. This saves you from downloading different version of product for yourself and lets you 'share' the software, specially the free ones. It also is great when you don't have an internet connection available at hand. Exceptions in Windows on Windows
As we have already seen that this does not work everywhere, we have a few exceptions to the 32 bit applications working on the 64 bit windows. most of the exceptions come from the section of 'games' which depend heavily on the DirectX which may or may not work with the WoW. this makes things complicated and users are advised that they use only the 64 bit version games they want to play for their 64 bit version Windows.
Also, it is to be remembered that WoW allows you to run your '32 bit application on 64 bit OS' but not the vice versa, which means that if you have a 64 bit version of application but you are running 32 bit version of Windows, there is simply no way that the 64 bit version will run on the 32 bit OS.
