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Application Virtualisation : An Application for the 21st Century

Virtualisation - The Future of Your Desktop Applications

Recently I was asked to examine a product called Software Virtualisation Solution (SVS) from Altiris together with an add-on product called DVS4SBC for use in the Citrix/Terminal Server environment.

Essentially these products enable your desktop applications to be effectively decoupled from the desktop operating system and run independently of the operating system or virtualised away from the main OS and are already redefining the way in which applications are installed today.

DLL Hell Still Exists Today

So what are we talking about here? Well let’s take for example the Microsoft Windows operating system.

As you may be aware, when you install any set of applications such as Microsoft Office or Adobe Acrobat, they update different parts of your computer system with their files and settings.

Eg the program files directory, the Windows Operating system directory and the Windows registry database which contains a list of configuration settings for your applications such as screen colours, default directories and so on.

This has caused numerous problems for the IT professional in terms of application migration, application deployment, registry cleanouts and updates, applications with conflicting files needing to be in the same directories (DLL Hell) to name just a few.

All of these can result in numerous support calls when any of these situations do occur. The bottom line is that when any of these situations occur, it can mean anything from support having to remove and reinstall the application but with a different configuration to totally rebuilding the user’s desktop in extreme cases.

Thus resulting in lost revenue due to the user’s downtime plus the cost of the computer engineer who has to go and fix the problem in the first place.

As of January 2008, there are currently two programs (Altiris Software Virtualisation Solution and Microsoft Application Virtualisation software formerly Microsoft Softgrid) that allow you to run a virtual application environment in such a way that your desktop applications will be installed without affecting any of your core operating system components.

If we take our original example, it is now possible to install as many applications as you like without any of them affecting the Windows operating system components; for example you could have three different copies of Microsoft Word (Word 2000, Word 2003 and Word 2007) all running concurrently without any impact on one another.

This would normally be impossible to do without having several virtual machines running on your operating system.

This is the concept of application virtualisation. Note for a few of the current differences between the two products you can listen to our Podcast with an SVS engineer.

Why Application Virtualisation

So now that we know what application virtualisation is, let’s take a look at why management should take a closer a look at products such as SVS. The major benefits of application virtualisation include:-

  • Efficiency Gains in Compatibility and Regression Testing

    Application virtualisation allows you to totally eliminate compatibility and regression testing. In other words, from a compatibility perspective, as each application is being run in its own virtual space, it will not impact on any other application’s DLL files or registry settings so from this perspective it cannot impact on the other application (obviously it will still affect the available memory for the other application).

    From a regression testing perspective, your support department can spend months simply testing the impact of security patches and other software updates on the application itself, on the coexistence with other applications and on the operating system.

    Having a virtual application environment enables you to totally bypass this process as you would simply have two versions of the software. One copy with the update and the copy previous to the update. Should the updated one fail, you would simply replace it with the original copy.

  • Application Plug and Play

    Applications can now be treated as modules with different user configurations, different patches and updates and simply slotted in and out of the desktop whenever they are required by the user. This reduces the amount of time a support engineer has to uninstall an application to make way for a newer or older version.
  • Reduced Support Calls
    As the applications are running in their own virtual environment, they will not be able to have any impact on each other, meaning less application downtime and so increase desktop worker efficiency.
  • An Application Migration for the 21st Century
    Whenever there has been any migration, whether it has been an upgrade to a new desktop OS or an upgrade of the application.

    There has always been teething problems. Now you simply install the new desktop O/S and deploy the required application modules. As mentioned before there is no need for any uninstall procedures or cleaning up the registry for old settings because the application virtualisation will not have affected the O/S registry in the first place.

All of these benefits can be quickly summarised into bottom line savings by using the Software Life Cycle examples and ROI (return on investment) metrics on

CitrixTerminal Services

One major area where products such as Altiris SoftwareVirtual Solution have already made large inroads is the CitrixTerminal Services environment.

In general, Citrix is widely used in large corporations especially in the area of branch office communications where the least amount of network traffic is required however there are several problems with trying to virtualise applications in this environment.

Problems with Application Virtualisation

Most of the problems I found were easily overcome by good organisation and planning or going to the vendor help site. The major show stoppers experienced by customers have been in the Terminal Server/Citrix environments. These problems include:-

  • Memory Leaks.

    Using virtualised software in a Citrix environment causes memory leaks after about nine or ten open sessions the Citrix server will run out of memory and crash (ie a blue screen problem will occur).

  • Security Risks.

    There is a security risk when using application virtualisation in a Citrix/Terminal server environment that allows users to see other people’s last opened documents. For example if we have six or seven users using Word 2007, the next user that logs on can see all or some of the others’ last opened documents even if they are held in their home directories. This is because SID information can be exchanged.

  • Profile Problems
    When users change their profile and application configuration settings, eg the bitmap on their desktop or the spell checker used in Outlook or word and they log out, then these settings are not kept. This occurs when an application is reset, or the user is getting connected to a different server.

E-Net Europe Ltd whose business is in the management of the desktop are offering a solution to these problems by supplying a program called DVS4SBC which is a product that loads on top of their SVS Pro software application and prevents all of the above problems from occurring.


I don’t normally give personal opinions in articles but frankly this technology will one day be a part of all operating systems or will eventually become the defacto standard as the way forward for managing and deploying applications on the desktop. This will occur in the same way that networks, imaging, the internet are all part of our corporate infrastructures and methodologies.

If you would like to find out more about software virtualisation and desktop management, give E-Net Europe a Call on 0208-754-7894 or check out (opens in new tab)

Ben Chai has been working in the computer industry as an engineer, trainer and industry expert for over two decades. He is author of Migrating from Windows NT to Active Directory and has been the editor for several IT magazines. At present he acts as a business director for a small IT consultancy called (opens in new tab) and a security analysis expert (opens in new tab)