[Grammar] data is used in singular/ plural form ?

[langue]

I googled about the question, and I found :


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Both are in use, and are accepted. Data (derived from datum - Latin) can be used either in singular or in plural sense, depending on whether it is used as a count noun (containing multitude of elements - answering how many) or a mass noun (being a collection as a whole - answering how much)
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How about the sentence below ?


Data A and Data B (is or are) not collectly stored.
In this case the data can be considered as a mass <combination of > data A&B ? , or it should be <are> in this case ?

Thank you

 

[emsr2d2]

Technically "datum" is the singular but you rarely see it used in BrE except perhaps in technical texts.

 

[GoesStation]

The sentence is unnatural either way. We don't describe a set of data as "data A".