Bubble memory is a sophisticated method of storing data that gets rid of the need for moving parts such as are required in tape machines and disk drives. Data is stored as tiny magnetic fields, in a medium that is made from magnetic film and semiconductor materials.
Bubble memory makes use of all the advantages of magnetic data storage, as well as the favorable aspects of electronic data storage. Advantages of electronic memory include rapid storage and recovery, and high density (a lot of data can be put in a tiny volume of space). Advantages of magnetic memory include non volatility (it can be stored for a long time without needing a constant current source), high density, and comparatively low cost.
Bubble memory seems to go through phases. Just as it is declared obsolete, someone comes up with a new and improved way to make it work. Check the Internet to find out its current status; enter “bubble memory” or “magnetic bubble memory” into a search engine.