A tape drive system that uses a tape cartridge having more than one file storage partition, sometimes herein referred to as “virtual tapes.” The tape file sub-system (which controls tape addressing) is identical to conventional single file storage partition tape cartridges, because: (i) a tape control sub-system controls writing of the multiple virtual tapes on a single tape cartridge, but communicates with the tape file sub-system as if the multiple virtual tapes were actually located on different physical tape cartridges; and (ii) a tape control sub-system controls reading of the multiple virtual tapes from a single tape cartridge, but communicates with the tape file sub-system as if the multiple virtual tapes were actually located on different physical tape cartridges. The multiple virtual tapes stored on a single physical tape cartridge are useful because they help circumvent certain “per tape restrictions” that are inherent in the tape file sub-system.