retrieval vs computer operation

retrieval and computer operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
retrieval	Yes	No	No	No
computer operation	Yes	No	No	No

As nouns, computer operation is a hypernym of retrieval; that is, computer operation is a word with a broader meaning than retrieval:

retrieval: (computer science) the operation of accessing information from the computer's memory
computer operation: an elementary operation that a computer is designed and built to perform

Other hypernyms of retrieval include machine operation.

retrieval (noun)	computer operation (noun)
the act of regaining or saving something lost (or in danger of becoming lost)	an elementary operation that a computer is designed and built to perform
the cognitive operation of accessing information in memory
(computer science) the operation of accessing information from the computer's memory