According to 1986 Disk Trend in 1984 two sided 3 was 35 of about a 2 0 M unit market 1983 was a 400k total market mostly one sided but the 1984 two sided at 700k was almost double the total 1983 one sided It sounds to me like a lot of two sided availability in 1984 and I will revise the edit to reflect this See what u think