For the confused..

A standard midi file is a sequence..but a sequence may not be a standard midi file..

SMF's began as a uniform GM map sequence..with the Roland Sound Canvas(GS) primarily leading the way (late 80's).

It is called "standard" because all products are able to use it with similar results..

The "old" days sequencing was more instrument specific..meaning it needed to be played back on the instrument used to record the data..as the early Roland recorders{data)....