It’s important that you don’t confuse SoftGrid virtualization (app-V) with how Windows Vista UAC performs redirection. With UAC, when an application attempts to write to or modify protected areas of the registry or file system, it is redirected to a user-specific view of the registry and file system. SoftGrid, on the other hand, uses a concept of truly virtualizing the application to the operating system—including all registry and file system components that make it up. But the elegance of SoftGrid is that it isn’t a single blob that defines an application. Instead, it consists of:
  • An SFT file of up to 4GB. This contains one or more applications and all of their dependencies except Windows dependencies, which are expected to be on the destination systems.
  • An OSD file of approximately 2KB. This contains a definition of how the application can be requested and executed. You can think of the OSD file as an EXE.
  • An ICO file of about 24KB. This is effectively a shortcut to launch the application.
  • An SPRJ file of about 13KB. This is used by the sequencer (the core of SoftGrid) to publish, open, update, and repair existing packages.
A comprehensive diagram of how SoftGrid Application Virtualization works is available at the Web site products/architecture.asp.