fixed disk vs magnetic disk

fixed disk and magnetic disk both are nouns.

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

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

fixed disk: a rigid magnetic disk mounted permanently in a drive unit
magnetic disk: (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 disc.

fixed disk (noun)	magnetic disk (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