<P> The 1991, Atari ST - PAD Stylus was demonstrated but did not enter production . </P> <P> In 1991, AT&T released their first EO Personal Communicator, this was one of the first commercially available tablets and ran the GO Corporation's PenPoint OS on AT&T's own hardware, including their own AT&T Hobbit CPU . </P> <P> The Compaq Concerto was released in 1993 with a Compaq - modified version of MS DOS 6.2 and Windows 3.1, a.k.a. Windows for PEN, with pen - entry and Wacom compatibility . Functionally the Concerto was a full featured laptop that could operate in pen - mode when the keyboard was removed . </P> <P> In 1994 media company Knight Ridder made a concept video of a tablet device with a color display and a focus on media consumption . The company didn't create it as a commercial product because of deficiencies of weight and energy consumption in display technology . </P>

Who manufactured the first commercially available tablet computer