Various embodiments of a computer system and methods are disclosed. In one embodiment, a computer system includes a host coupled to a backup store. The host backs up a dataset to the backup store. The dataset comprises data entities and application-specific metadata describing the data entities. The application-specific metadata enables an application to use the data entities. The host: mounts the backup store for read/write access by the application, accesses the backup store with the application, selects a data entity, and performs an operation on the data entity in the backup store using the application. The operation may comprise verifying that the data entity is valid and usable in the context of the application or creating an archival backup of the data entity on a backup medium. The backup store may be a disk-based backup store and the backup medium may be a tape-based backup medium.