Commentator's dread: champ producing masses of data? (8)

I believe the answer is:

terabyte

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'of data?' is the definition.
The definition suggests a singular noun which matches the answer.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for terabyte that I've seen before include "1000 gigabytes of data information" , "Large unit of computer memory" .)

I've seen this clue in The Times.

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