Not quite an answer to your question, but perhaps close: A world without **digial** electronics.

Give [analog computers][1], both mechanical and electronic, a better start. Digital computers could be overshadowed in the way that [VHS defeated Betamax][2]. It might help if there was no world war at the time to push code-breaking applications. [Punch card machines][3] for digital sorting would remain incompatible with computers for analog calculations. 

  [1]: http://en.wikipedia.org/wiki/Analog_computer
  [2]: http://en.wikipedia.org/wiki/Videotape_format_war
  [3]: http://en.wikipedia.org/wiki/Unit_record_equipment