Random access time to data stored on LTO tape by incorporating stacked cartridge memory (CM) modules

A tape cartridge having dual cartridge memory modules to provide memory redundancy, and a method and apparatus for providing redundancy of cartridge memory information within a tape cartridge. The tape cartridge comprises at least first and second cartridge memory modules, each of which stores an identical set of critical information. Each of the first and second cartridge memory modules includes enough critical information to recover from a failure of either of the cartridge memory modules. The method comprises the steps of providing at least two cartridge memory modules in the tape cartridge, and storing an identical set of critical information in each of the two cartridge memory modules. Each of the two cartridge memory modules includes enough critical information to recover from a failure of either cartridge memory module. In a preferred embodiment, the CM modules are stacked one on top of another and increase the amount of space available for tape directory storage.