I know the different between RAM and disk in a server context (what sort of programmer wouldn't?!), but I've worked pretty exclusively in no-persisted-storage environments (mostly Heroku) for ~5 years now, where referring to "saving" files/data outside of a DB context almost exclusively means "save to memory" and I routinely run into problems whenever my stack requires downloading any sort of third-party library that would have to persist outside of RAM (e.g. downloading NLP libs).

When you abstract "storage" into "my library/tools save state somewhere" (and god forbid you include localStorage into the mix!) and don't deal with the hardware itself, I could see how a lot of new-ish coders wouldn't be able to differentiate RAM and disk.