A data storage cartridge comprises data storage media configured to store data for read and/or write access, wherein the data may be arranged in a plurality of partitions; and a plurality of cartridge memories. A control system, for example of a data storage drive, is configured to allocate at least portions of capacity of the data storage media to cartridge memories of the data storage cartridge; and to provide information defining the allocated portions of capacity to the cartridge memories. Each of the cartridge memories may have a separate user and thus provide access for that user to separate partitions.