Nashville Notation

[googledawg]

we got into a discussion on alt.guitar about Nashville Notation, which
i THOUGHT meant using plain "arabic" numbers for chord roots, i.e. ; I
2m 3m 4 5 6m (don't think i ever SAW a vii)
rather than I-ii-iii-IV-V-iv-viidim

and a dominant seventh might be 5-7 don't know what happens with
slash chords - actually i INVENTED nashville 45 years ago, if that's
all it is - 111144115415. THEN i learned to put down four bars on a
line, and all of a sudden AABA came into focus.

1111
4411
5415

4411
2255

Any Experts or highly opinionated commentors? or anywhere in between...