- Whenever a new OS is introduced into the organizations infrastructure the main concern is to deal with how existing applications will impact the OS and provides an opportunity to revisit what is owned and a way to standardize the environment with best practices and hence reduce the total cost of ownership. It requires finding various application compatibility solutions already available which deals with the migration issues and provides compatibility methods to overcome the impact.
- In a typical migration scenario an entire application portfolio (possibly thousands of applications) must be identified, rationalized, and tested for compatibility with the new host operating system. Incompatible packaged applications are fixed during a remediation process then repackaged and retested to help ensure proper installation and functionality on the new operating system.
- Application incompatibilities arises for the following reasons:
- Change in the security model imposed by the new operating system
- Adoption of newer Industry Standards which invalidates older mechanisms
- More restrictions brought forward in the kernel to prevent unlawful attacks
- Restrictions in inter-process communication
- Sometimes a feature on which an application has relied is retired from windows.
- In windows vista,certain applications are written with hard-coded versions and hence will fail on the new operating system whenever the version changes.
- Any time operating system behavior is changed there is a possibility that an application has taken a dependency on the previously implemented behavior.
- Several legacy components from earlier Windows releases are not present in Windows Vista or Windows 7 :
- Kernel-mode printer driver support.
- Windows Help for 32-bit applications (WinHlp32.exe).
- Microsoft FrontPage server extensions.
- Direct 3D Retained Mode (D3DRM).
- Web Publishing Wizard.
- Windows NT LAN Manager Security Support Provider (NTLMSSSP) Service.
- Network Dynamic Data Exchange (NetDDE).
- Microsoft Graphical Identification and Authentication (GINA).
- Windows Gallery applications.
- Windows registry reflection.
- In organizations supporting windows XP, migrating to Windows 7 will resemble the efforts required to move to Windows Vista. In organizations supporting windows Vista, migrating to Windows 7 will require a less effort to test and validate as compared to moving from windows XP to Windows 7 as most of the features are common with Windows vista.
- As the migrating issues can have a more impact while moving towards Windows 7 deployment, the organizations should adopt a full proof Application compatibility project which aims to provide an opportunity to study the various primary compatibility methods available and ease the compatibility process. Apart it helps to standardize the process and reduce the costs.
Application Compatibility Process:
STEP1: Creating an Application Inventory
The first Step is to create an application inventory list so it’s easy to track the compatibility issues. Several tools to perform asset inventories are available. Some are
- The Microsoft Assessment and Planning (MAP) Solution Accelerator and the Application Compatibility Toolkit (ACT).
- For larger enterprise environments, Microsoft includes asset inventory functionality in System Center Configuration Manager and in the Asset Inventory Service in the Microsoft Desktop Optimization Pack (MDOP)
The Second Step is to analyze the list of applications inventory for compatibility issues which will help to reduce time and overall cost. The simplest way is to standardize the version of an application that is used across the organization that has the same functionality. As this will avoid conflicts and have a smooth functioning of application in the environment.
STEP3: Testing and Remediating Application Compatibility Issues The third Step is to test and remediate the application compatibility issues as analyzed above.
Different Remediation technology available :
1. Different types of remediation technologies are available from different vendors to perform remediation and mitigate compatibility issues. Automated tools and other tools are used depending upon the type of application such as mission critical applications (tier-1) or Business critical applications (tier-2, 3) or other applications (tier-4, 5).
2. Before moving to perform remediation of third party application it is best to search and understand the vendor policy for the same and lookout for a compatible version available. This guarantees that the application works as expected and support is available Also remediation is not a primary fix for the application, the corresponding compatible version needs to be search for windows 7 compatible version or in house recode method, re-engineering according to the new standards imposed by OS (windows 7).
3. To remediate applications is an important task. Certain applications will require to be purchasing a new version whereas some requires the following technology to be used.
- Application Shimming :Shims are Windows Application Compatibility Infrastructure (shim engine) which provides one option for resolving compatibility challenges with Windows 7. By applying Application Fixes (shims) to a specific application, you can modify the behavior of Windows, but only for that application.
- Application Compatibility toolkit.
- Terminal Server.
- Virtual Desktop Infrastructure (VDI).
- Recode/Upgrade Application.
- Several virtualization technologies have been put in use, such as Windows XP Mode, Microsoft Enterprise Desktop Virtualization (MED-V), and Application Virtualization (App-V), to overcome application compatibility issues.
- Many other Third Party vendor tools also available.
- Automated Tools such as AppDNA, Change Base AOK
The following graphic helps explain the processes and methods for mitigating application incompatibility within an enterprise.