Bubble memory was a type of computer memory that retained information even after power has been removed. It was used by the Logopolitans, (TV: Logopolis) as well as being produced on Earth by Geocomtex. (PROSE: Products)
The Fourth Doctor took it so he could use it on the Pharos Project computers. (TV: Logopolis)
Bubble memory were listed among Geocomtex's "world-gripping" products on a page on their website. (PROSE: Products)