Friday, 1 August 2008

The 6 Laws of AOK Compatibility

There is much in the news about Vista and migrating to Vista recently. Of prime concern is application compatibility which when simply put means getting applications to work on the target desktop or server environment. There is a lot of complexity in getting applications working - whether on Windows XP or Vista or the soon to be released Windows Server 2008.

And this is where I think there is some general confusion. Application compatibility is not simply about getting applications to function or work correctly on an Operating system such as Vista. Ensuring that application work correctly really means getting the application to work on the target platform and which involves the following;

1. Ensuring Operating System (e.g. Vista ) compatibility
2. Ensuring the availability of the complete and correct versions of middleware
3. Ensuring that applications do not conflict with each other (on install and un-install)
4. Ensuring that user environment is correctly setup and available

Breaking the application compatibility question into these four layers delivers a fundamental step change in the understanding and resolution of application compatibility issues. No longer can we just get one application to work on a desktop, we need to get several or even tens of applications to successfully install, update and un-install without breaking other applications. We now have large, complex and constantly changing middleware layers (Java, Crystal Reports, ODBC) that applications depend upon. Adding to the confusion, differing applications may require different versions of middleware components or worse, may ship from the software vendors with incomplete ("middleware fragments") dependencies which may allow the application in question to function but may prevent another application from working or even installing successfully. Viewing application compatibility with these four layers in mind requires a paradigm shift; to the Platform Integrity model which takes into account all of the requirements to successfully install, use and maintain applications.

To further this goal, AOK has developed the "AOK Laws of Application Compatibility" which include;

1. Enable the installation package to install successfully
2. Provide the application the required privileges and security access levels
3. Ensure that the required dependencies (middleware) are available and complete
4. Ensure that applications do not conflict with each other on installation, updating/patching or un-installation
5. Ensure that the user environment is correctly configured
6. Ensure that future changes/patches/updates do not adversely affect any of the four layers; the OS, the Middleware layer, Applications or the User Environment

When you follow these guidelines, your chances of successfully developing, deploying and maintaining your application portfolio are significantly increased; today and when dealing with future changes.

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