This new high density 330TB magnetic tape cartridge was created in labs, using all new concepts.  It will be very expensive if it materializes commercially in the future and represents revolutionary breakthroughs in magnetic tape technology (often used to backup data)

https://arstechnica.com/information-technology/2017/08/ibm-and-sony-cram-up-to-330tb-into-tiny-tape-cartridge/

IBM and Sony have developed a new magnetic tape system capable of storing 201 gigabits of data per square inch, for a max theoretical capacity of 330 terabytes in a single palm-sized cartridge. For comparison, the world’s largest hard drives—which are about twice the physical size of a Sony tape cartridge—are the 60TB Seagate SSD or 12TB HGST helium-filled HDD. The largest commercially available tapes only store 15TB. So, 330TB is quite a lot.

To achieve such a dramatic increase in areal density, Sony and IBM tackled different parts of the problem: Sony developed a new type of tape that has a higher density of magnetic recording sites, and IBM Research worked on new heads and signal processing tech to actually read and extract data from those nanometre-long patches of magnetism