I wonder if a camera obscura would be enough to create the focused image instead of having to bother with lenses.
Circular flat objects are spelled disc, with a C.
Hence floppy disk, hard disk, but compact disc.
(MiniDisc is the only exception to this rule that I can think of, probably because it is a trade mark.)
> in the case of flat, rotational data storage media the convention is that the spelling disk is used for magnetic storage (e.g. hard disks) while disc is used for optical storage (e.g. compact discs, better known as CDs). When there is no clear convention, the spelling disk is more popular in American English, while the spelling disc is more popular in British English.
I didn't know that disk = diskette was a British thing! And I am British. So I guess that makes sense.