How will you deal with 32-bit apps in an x64 world?

We've been talking quite a bit recently about how Citrix just released a slew updates for XenApp running on 32-bit Windows Server 2003. We also know that they're now busily working on "Parra," the next major release of XenApp which will run on Windows Server 2008 R2.

We’ve been talking quite a bit recently about how Citrix just released a slew updates for XenApp running on 32-bit Windows Server 2003. We also know that they’re now busily working on “Parra,” the next major release of XenApp which will run on Windows Server 2008 R2.

And of course everyone should know by know that all future versions of Windows Server (starting with 2008 R2) are x64 only, which means that all new Remote Desktop Servers are x64 only from now on, which means that all future versions of XenApp will be x64 only from now on.

That would be fine, if every single app was x64 compatible. But they’re not. Anything with kernel components (drivers, etc.) won’t run on Windows x64 unless it’s been specifically compiled for it. And 16-bit apps are out. (Which isn’t too much of a problem in today’s world, although every once and a while we come across a 32-bit app with a 16-bit installer. D’oh!)

Never fear, though, because everything we’ve been talking about over the past few years has been that application and desktop delivery environments of the future will be “hybrid” solutions (much like they are today). We’ve talked (and talked and talked) about hybrid VDI solutions (local VMs, multiple VMs, OS streaming, remote VDI, TS, etc.)

Moving forward, we should think about how we’ll mix 32-bit and x64 OSes strictly for the purpose of app compatibility. (After all, if we didn’t need 32-bit for app compat, then we’d be 100% x64 today.

A few possible scenarios:

  • x64 clients with 32-bit VMs for non-compatible apps. (Hey, just like Windows 7’s XP mode!)
  • x64 servers and clients, with some 32-bit Terminal Servers / XenApp servers for hosting remote seamless 32-bit apps. (Thanks AppDetective for that suggestion!)
  • A mix of 32-bit and x64 VDI VMs?
  • Only run the 32-bit apps that will run on Windows x64.
  • Something else?

What about you? How do you plan to deal with 32-bit apps as the mainstream moves towards x64?

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That's were Server Virtualization (for 32 bits OS on x64 hardware) and Server Provisioning (to keep using the same image whatever how many and where you make them run) are very important now... It will help to keep W2K3/32bits up and running wherever support is available.


x64 Windows has support for 16-bit installers in that it detects several known setup programs and automatically replaces them with compatible 32-bit versions.


Working with Application Delivery, the Applications will decide were to go for server OS.

Many applications, for example, are not supported on Windows 2008 Yet.

Many of them, again, are not supported on x64 servers.

And talking about 16bit apps, I've seen many applications, mainly 32bits but with small 16bits parts.

This would be too huge for some customers to redevelopp their critical business applications, even if Microsoft has decided to push x64.

I think that we'll have to use Windows 2008 / x64 when applications are compliant and keep good old Windows 2003 / x86 for non compliant applications.

Just to illustrate : I've seen some weeks ago a customer choosing to install XenApp 4.0 (even if the product has reached its end of life) just because that's the only supported version for its critical business application.


@ Helge Klein

I've not had such luck.  I've had many clients with 16-bit installers for 32-bit apps.  Windows Server 2008 x64 (or simply R2) will not install it. It just doesn't work.


I have the extremly bad luck of having to support 16-bit applications aswell as 32-bit applications with kernel mode services.

So, now that I'm tossing away the old CPS 4.0 environment (because of other reasons) I'm left with WIndows 2008 R1 32-bit that Citrix has abandoned and prolly never will alow to run side-by-side with R2 dittos whenever this parra comes along...

Oh the agony!! Shoot me,somebody!


We test apps for 64 bits compat using our automatic analyses tool. Meaning that we have tested a very very large number of apps already.

The bad news seems to be that as much as 40-50% of apps have some nasty 16-bit elements hidding somewhere. Not only in the installer but also in the drivers, bins, etc... Some will simply break the apps, other will simply kill a functionality.

The scenario Pierre describes is definitely what we see happening today in a number of global companies: a progressive approach where they identify and run as many apps as they can on 64-bits boxes and leave the rest in 2003 32-bit.  


I can get about 95% of my apps to run just fine on x64. The rest I can terminal serve.


I agree with Pierre, regardless of how much the industry pushes for 64bit or MS pushes for 2008, companies will hold on to what is necessary for their business to run. I'm all for 64bit servers wherever possible but the real world isn't one of those utopian case studies.

When faced with the cost of rewriting applications or remaining on a 32bit platform, I think many companies will choose the most affordable of the two given our tough economic times.

In our case, we wanted to go Xenapp 5 on 64bit Server 2008 but application compatibility is the only reason we did not. We develop over a hundred in house apps and the lesser of two evils was to go 4.5 on Server 2003 and run 64bit on every capable server in our farm. We have about a 70/30 split where 30 percent of the hardware supports 64bit. The idea is to increase the user density on these 64bit servers and lessen the overall number of servers in our farm while leaving several 32bit servers for the laggard apps.


For all of us sad people living in the cruel reality...

With Windows 2003 ending mainstream support next summer, all we have is WIndows 2008 R1 32-bit to handele our issues.

Clearly 2008 R1 is not fine enough on it's own weight (2008 R2 could be made to be so...)

So, I guess a lot us need good 3:d party support.

Thus my grief:

Why, oh why have Citrix abandoned us on 2008 R132-bit world?

Can Brian or anyone else in the spotlight please put some attention to this?