§§§FAQ

2. What is the .NET Framework and its role in delivering no-touch smart client deployments?

The .NET Framework provides a number of fundamental capabilities, which means that we no longer have to face the difficult usability versus manageability tradeoff.

The .NET Framework has very effectively solved the problem of version conflicts between assemblies shared by more than one application. A .NET application or assembly has a strong coupling to the assemblies and components they depend on. Assemblies are annotated with meta-data, which specifies both their exact version and the versions of all dependent assemblies. Multiple versions of the same assembly can be installed side-by-side so that all applications can be run with the exact same version of the assembly that they were built and tested against.

This assembly binding mechanism also provides important security safeguards. Assemblies can be cryptographically signed to prevent malicious code being run inadvertently, either through tampering or through luring attacks. In addition, .NET Code Access Security (CAS) allows assemblies to be granted specific permissions so that they can be used in semi-trusted scenarios. The .NET runtime ensures that assemblies can only carry out operations for which they have been granted permissions. The .NET Framework defines a flexible evidence based infrastructure for determining which permissions to grant an application or assembly.

These features effectively address application stability and predictability, but what about deployment? Assemblies do not need to be registered on the local machine so they can simply be copied to the machine before they are run. This greatly simplifies the deployment of the application. Alternatively, assemblies can be downloaded from a central server, either at install or at run time.

.NET also provides a deployment feature called No-Touch Deployment, which allows applications to be run on a URL. When the user clicks on the URL, the runtime automatically downloads the application, and all related assemblies, to a special download cache. This mechanism also checks for version updates so that the user never has to worry about whether they are running the latest version of the application or not.

Applications deployed in this way are only granted a very limited amount of permissions by default and are unable to access the local hard disk or access any network services, apart from the service from where they were downloaded. Additional permissions can be granted at the user, machine, or enterprise level if required

Of course, the .NET Framework provides quite a few other features that affect how smart client applications can be designed and built. Of particular important are the Microsoft® .NET Windows Forms classes. These classes provide very rich user interface controls and give developers in all languages a common UI framework to work against, m aking development and testing much easier. The .NET Framework also provides many facilities for connecting to network services, such as SOAP-based Web services, and provides comprehensive XML support.