I've got one. I was so cool in 1987 or so, carrying the
M100 and a disk drive, writing articles on airplanes.
I even remember using CompuServe via the M100.
It uses the serial port. I seem to remember utilities for
the PC that pretend to be a disk drive for an M100 in this
fashion, as well as tools that would let the drive connect
to the PC. I think the drive came with a disk containing
a utility or two.
- John