> "Data" is the plural of "datum."

Actually, in most computer documentation it is used as a 'mass noun'.
As such 'data is returned' is correct [1].

Since English is a language defined by its usage, there is nothing
wrong (except the inconsistency).

The www.opengroup.org/onlinepubs/009604499/functions/read.html
page has, for instance, 'until there is no more data to be retrieved.'

	David

Compate to the use of other mass nouns like 'water'.

-- 
David Laight: david@l8s.co.uk