Nov 20, 2018 ... Before smartphones ruled the roost, personal digital assistants (PDAs) walked
the Earth. ... These innovations can be traced back to Jeff Hawkins, who formerly
worked for tablet pioneer GRiD and designed the Zoomer PDA for Tandy and
Casio. ... produced over a dozen color touch-screen devices, all of which ran
variations of Microsoft's Pocket PC/Windows Mobile operating system.