I learned today that the concept of "sweeping time" (period
during which the signal is being displayed in an analog
scope) does not apply to digital scopes. The corresponding
concept is "sampling" which keeps going continuously at
a selected rate. I also learned that, as confirmed by Brian,
a "record" is a set of data points from which a single
shape is constructed on the screen, or saved as a file for
possible future examinations.
But the concept of two triggering time bases (each with
its own selectable delay) is still a mystery to me. Perhaps
I will learn about this in "Digital Storage Oscilloscopes,"
the 1997 book by Jan Hickman.
While "fishing" over the Internet I found some useful
tutorials, for example, at: