Ramac had fifty 2 foot diameter double sided platters, and could hold a
total of about 5MB.'
The IBM 350 disk storage capacity was 5 million 6-bit characters == 3.75
MB.
But VERY soon they lengthened the slot [of the 5¼-inch FDD] for 40 tracks
..."
VERY soon they in this case is in 1977 a number of vendors such as MPI
and Pertec started and the industry followed, including Shugart Associates.
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
Tom
