A magazine-based data storage library in connection with a disk drive-based archive storage system is described that essentially generates parity data for tape formatted data streams (stored to tape cartridges) that do not align by way of data blocks or file marks. Data streams intended for tape storage sent to tape cartridges are also sent to a disk drive storage system via an encoder where parity of the data streams can be generated. More specifically, the encoder digitally formats tape blocks and tape marks (as well as other tape formatted structure) in a digital stream of data that can be added to other encoded digital streams of data to generate parity. To reconstruct a specific tape cartridge from a tape set, the encoded data from each of the tapes in the tape set are subtracted from the parity data and the remaining encoded data is decoded and sent to a designated tape cartridge.