Iirc (it's been a while), Interactive Unix (full?) install required some 40 (forty!) 5 1/4" floppies (I believe 1.2MiB) anno 1992 or so. Linux (SLS) install was (a little later) so much smaller, even with X11 and TeX, as it had shared libraries (somewhat new in the *nix world then).

Ah, good times ;-)