Abstract: A tape drive unit includes a tape driver for writing/reading information on/from a magnetic tape when a tape cassette including the magnetic tape is loaded onto the drive unit, a memory driver for use when the loaded tape cassette includes a memory for storing management information for managing the writing/reading of information on/from the magnetic tape, the memory driver writes/reads the management information in/from the memory, a detecting unit for detecting retry-permission/inhibition information (stored in the memory) which instructs a permission or inhibition to retry the writing/reading of information on/from the magnetic tape, and an operation-mode setting unit for setting the operation mode of the tape driver, based on the retry-permission/inhibition information.