I'll toss a couple of old IBM magtape variations out: The IBM 728, used on SAGE. 7 track, but not your daddy's 7 track. 3 data tracks either side of a central clock track. Different from either of the pre- and post-series drives (727 and 729) that we have grown to love.
And, of course, the 7340 hypertape. Inch-wide cartridge tape, 10 tracks, circa 1961. The 7000 series (e.g. 7070, 7090) used only 8 of the tracks. Does anyone know if the extra tracks were intended for use by the 7030 STRETCH? --Chuck
