Before any resource can be created, it must first get a resource tag from the NetWare OS (for reference purposes). To obtain a resource tag from the OS, resource creators must provide a valid signature. The OS uses these signatures to keep track of routines it needs to call on behalf of a resource (such as cleanup routines).
When Media Manager is invoked, it registers a unique signature for each class with the OS. When resources are created in Media Manager, the resource creator can use one of the class signatures Media Manager has reserved to get a resource tag from the OS.
Resources created in Media Manager also require a resource tag. To obtain a resource tag prior to registering an object in Media Manager, use the OS function call AllocateResourceTag to pass the class signature for the class to which the object is eventually going to be registered.
When a resource is no longer used, the OS informs Media Manager that a resource tag it controls has been released. This allows Media Manager to release other resources that are relying on the original resource. Media Manager then cleans up after the released resources (such as returns allocated memory).