1. A method of handling a Network Data Management Protocol (“NDMP”) backup or copy operation, the method comprising: receiving an original NDMP backup data stream from a client; modifying the received original NDMP backup data stream by performing the following modification procedures upon the original NDMP backup data stream: deduplication, encryption, and compression, wherein the modification procedures create a modified version of the NDMP backup data stream; storing the modified version of the NDMP backup data stream in stored chunks, wherein each chunk is addressable by a physical offset and a physical length, wherein each chunk represents a modified version of a contiguous subset of the original NDMP backup data stream, and, wherein the client associates a logical offset and a logical length with the contiguous subset of the original NDMP backup data stream that is represented by each chunk; and, for each stored chunk, associating the stored chunk with: the physical offset and physical length that permits addressing of the chunk, the logical offset and logical length that the client associates with the contiguous subset of the original NDMP backup data stream that is represented by the chunk, and receiving a request for a certain subset of the original NDMP backup data stream, wherein the request includes a logical offset and a logical length; using the received logical offset and logical length to: identify a stored chunk that comprises a modified version of at least a portion of the requested subset of the original NDMP backup data stream, and determine a physical offset and a physical length that permits addressing of the identified chunk; reading at least a portion of the identified chunk using the determined physical offset and physical length; converting the portion of the identified chunk by reversing the modification procedures that were previously performed upon the original NDMP backup data stream in order to create a converted version of the portion of the identified chunk; and, sending data from the converted version of the portion of the identified chunk that is at least a portion of the requested subset of the original NDMP backup data stream.