Windows Server 2003 is dominant today in Citrix XenApp environments. In fact we are currently at the peak (or nearly so) for a W2k3 installed base for Windows servers in general. As our customers look forward they will be faced with some potentially thorny issues when moving to Windows Server 2008. The main question is whether to go to the first W2k8 release (I will call it "R1" for the sake of simplicity) which includes both 32-bit and 64-bit versions or to skip R1 entirely and go with the recently released R2 which only supports 64-bit.

Based on several discussions we have had with partners and customers there seems to be a continuum of opinions. On the one extreme we hear folks saying that they will stick with 32-bit until it is ripped away from their cold, dead hands. These are among the more conservative who fear the expense and churn of having to validate all of their thousands of 32-bit applications on a 64-bit environment. They have told us they will stay on W2k3 until extended support is complete and then probably go to R1 and milk that for all it's worth to avoid the inevitable. That would mean sticking with a 32-bit OS until possibly 2018 (should we all be retired by then?) going by the Microsoft Lifecycle table for Windows Server 2008! On the other extreme are a few bleeding edge types who have decided to skip R1 and go directly to R2 and bite the 64-bit bullet at the same time as they migrate their environment from W2k3 to the newer OS. In between are those who will move cautiously if begrudgingly over time to the new OS version to avoid falling into the extended maintenance window.

One of the main concerns is, of course, that R2 is 64-bit only. While Microsoft has been stating for some time that Windows on Windows 64 (WoW64) will solve the problems associated with running 32-bit apps on x64 platforms, many customers are still worried about 32-bit apps with 16-bit installers and the ever-present 32-bit drivers. Not to mention, 16-bit apps. None of these will not work on WoW64 environments. On the other hand, don't customers have to test all their apps when transitioning from one OS platform (W2k3) to another (R1 or R2) anyway? What extra work is involved when validating apps on x64 versus just transitioning from one version of the OS to another? Of course out lives would be easier if everyone hopped to the new OS version ASAP so we did not have multiple platforms to support but the reality is quite different. We need to know what your thoughts and plans are on this one.

So this brings me to my questions for the community:

• What do you have to say as customers and partners?
• Will you stick to 32-bit as long as humanly possible?
• Do you have older apps with 16-bit installers or 16-bit apps? What is the plan there? Re-write or retire?
• What will you do about 32-bit drivers? Printer drivers? Will XenApp's Universal Print Driver solution be the answer?
• What has been the experience for those who have made the switch to 64-bit?

Give us your comments and take the poll below.

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Summary

This article describes how to run Web Interface 5.0 in a 64-bit Internet Information Services (IIS) process.

Background

This article applies to Citrix Web Interface 5.0 running on Microsoft Internet Information Services (IIS) 6.0 or 7.0 with an appropriate version of Visual J#.NET 2.0 Second Edition on a 64-bit computer.

Web Interface 5.0 is a .NET application that is compiled so that it can be used on both 32-bit and 64-bit versions of ASP.NET. Web Interface makes use of Visual J# and 64-bit support is added by Visual J#.NET 2.0 Second Edition. This allows the Web Interface to run inside a 64-bit IIS process.

The ability to run inside a 64-bit process can prove particularly useful on IIS 6.0, where the entire IIS Web site is either a 32-bit process or a 64-bit process. This makes it easier for the Web Interface to coexist with 64-bit Web applications on the same IIS site.

Procedure to allow the Web Interface to run as a 64-bit process on IIS 7.0

1. Open the Microsoft Management Console (MMC) IIS Manager snap-in on the server running the Web Interface.

2. In the left pane, click Application Pools and, in the Features View, select the application pool that your Web Interface site uses (usually called CitrixWebInterface5.0.xAppPool).

3. In the Actions pane, click Advanced Settings.

4. In the General section, change the Enable 32-Bit Applications setting to False.

To allow the Web Interface to run as a 64-bit process on IIS 6.0

1. When you install the Web Interface, allow the installer to switch IIS to 32-bit mode.

2. To switch IIS back to 64-bit mode and register the 64-bit version of ASP.NET, click Start, click Run, type cmd, and then click OK.

3. From the command prompt, type the following command to disable 32-bit mode:

cscript <systemdrive>\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0

4. Type the following command to install the version of ASP.NET 2.0 and to install the script maps at the IIS root and under:

<systemroot>\Microsoft.NET\Framework64\version\aspnet_regiis.exe -i

where version is the build version number of ASP.NET.

5. Open the MMC IIS Manager snap-in on the server running the Web Interface.

6. Click Web Service Extensions under the server running the Web Interface and ensure that the status of the appropriate ASP.NET version is set to Allowed in the details pane.

• More Information

For more information about ASP.NET on IIS 6.0, see Microsoft Support Article 894435