AppDisks is an application layering solution introduced in XenApp and XenDesktop 7.8. AppDisks separate applications and groups of applications from the operating system, enabling you to manage them independently.
AppDNA allows XenApp and XenDesktop to perform automatic analysis of applications on a per-AppDisk basis. Using AppDNA helps make the most of the AppDisks feature. Without it, application compatibility is not tested or reported.
AppDNA reports help identify issues and suggest remediation steps. For example, AppDNA can identify applications that have common dependencies such as .NET, so you can install them on a single common base image. AppDNA can also identify applications that load early in the OS startup sequence, so that you can then ensure they behave as expected.
For more information, see the XenApp and XenDesktop AppDisks article.