fixed disk vs magnetic disc

fixed disk and magnetic disc both are nouns.

Word	Noun	Adjective	Verb	Adverb
fixed disk	Yes	No	No	No
magnetic disc	Yes	No	No	No

As nouns, magnetic disc is a hypernym of fixed disk; that is, magnetic disc is a word with a broader meaning than fixed disk:

fixed disk: a rigid magnetic disk mounted permanently in a drive unit
magnetic disc: (computer science) a memory device consisting of a flat disk covered with a magnetic coating on which information is stored

Other hypernyms of fixed disk include disc, disk, magnetic disk.

fixed disk (noun)	magnetic disc (noun)
a rigid magnetic disk mounted permanently in a drive unit	(computer science) a memory device consisting of a flat disk covered with a magnetic coating on which information is stored