Eric Smith wrote:
Memorex introduced the first commercially-sold 8"
read/write floppy
drive, the 650, and later a 651 with faster seek times. These were
hard-sectored and had the sector/index hole near the outer edge, and
spun at 375 RPM. I don't know whether the diskettes used by the Memorex
65x drives were interchangeable with Minnow disks, but my box of Memorex
disks were presumably for the Memorex 65x drive. I've heard that the
65x drive was used in some early word processing systems.
They were also sold by AED in the 2500 floppy disc subsystem.
Burroughs also used this style floppy. There is a notch in the outer case
on those.