AT&T

AT&T invented the transistor, UNIX, C, C++, and a wide variety of other computing advances. Despite this overwhelming research power, they never became a successful computer manufacturer. They had experience in telephone switching systems and parlayed it into advanced digital designs, but the company has rarely focused on computing as a sector as important or more important than communications. Their most recent advertising and research seems to suggest otherwise, but the field seems fragmented enough to keep this corporate giant from taking very much of the pie.