USB and Floppy Timeline By bennkittler Oct 1, 1973 250K, 8 inch, single-sided, single-density Oct 1, 1976 500K, 8 inch, 2-sided, single-density Oct 1, 1977 1.2MB, 8 inch, double-sided, double-density Oct 1, 1978 320K, 5.25 inch, 2-sided, 8-sector Oct 1, 1980 160K, 5.25 inch, 1-sided, 8-sector Oct 1, 1981 180K, 5.25 inch, 1-sided, 9-sector Oct 1, 1984 720K, 3.5 inc, 2-sided, 9-sector Oct 1, 1984 1.2MB, 5.25 inch, 2-sided, 15-sector Oct 1, 1986 1.44MB 3.5 inch, 2-sided, 18-sector Oct 1, 1987 2.88MB, 3.5 inch, 2-sided, 36-sector Oct 1, 1987 360K, 5.25 inch, 2-sided, 9-sector