Data storage tape cartridge with exposed base plate detum for tape registration

A data storage tape cartridge having an exposed base plate datum for improved tape registration. The data storage tape cartridge includes a housing defined by a first housing section and a second housing section, a base plate, at least one tape reel and a storage tape. The base plate is disposed within the housing and includes a reference portion that is exposed through a protected opening in the first housing section. In one preferred embodiment, the first housing section protects the base plate, including the reference portion. The at least one tape reel is rotatably associated with the base plate. Finally, the storage tape is maintained by the at least one tape reel within the housing. Upon insertion of the data storage tape cartridge into a tape drive, a registration device engages the reference portion of the base plate to determine and precisely control location of the storage tape relative to a read/write head.