32 bits apps awareness on 64 bits OS, in the Citrix XenApp / Presentation Server forum on BrianMadden.com

I am unsure as to what answer you want, but I will answer your question as you proposed it.

No, 32 bit apps are not aware they are on a 64 bit OS. When a 32 bit application is executed, the OS will see it is a 32 bit application (or driver) and basically run what they call a windows on windows instance and run that application in basically a 32 bit machine.

I'm also not sure exactly about what you are asking, so I'll answer what I think you might be asking:

1. Will my 32bit apps work on Windows 2003 x64 - probably yes but you should verify. Most applications will work without a problem, and as noted above, will probably not notice the difference. However there are a few exceptions. The most notable exception is that if the application relies on a device driver then you must have a 64bit version of that device driver. Indeed, the lack of 64bit device drivers has been a major inhibitor to the usage of x64 Terminal Servers.

2. Does every SBC product support Windows 2003 x64 - the answer to this is an emphatic NO. Currently the only SBC solutions that support x64 that I'm aware of are Citrix and Ericom PowerTerm WebConnect (Ericom PowerTerm WebConnect also supports Windows Server 2008 x64). With regard to specific SBC utilities you will need to verify with the vendor.

Dan