On Thu, Jun 11, 2026 at 3:31 PM Tom Gardner via cctalk <[email protected]> wrote: > “Then 3.5" > The Epson PF10 had 40 cylinders with 67.5 tracks per inch, but > everybody else immediately went to 135 tpi, …” > • The first 3½-inch is generally accepted as the Sony OA-D30V shipping in > 1981 at 135 tpi. There were earlier drives smaller than the 5¼-inch. The > Epson PF-10 was much later circa, 1984
I think I have one or two Sony OA-D3XV drives, I'd have to go up in the attic to look for a never-released terminal server product I worked on in 1984-1986 to find out exactly which model. I remember it had a chunky full-height Sony 3.5" drive but I don't remember if it was so old we had to pinch the shutter on the diskettes or if it had an autoshutter mechanism. The first 3.5" drives I used were on a 128K Mac, around July/August 1984 and I definitely wasn't pinching the shutter on those. -ethan
