Between 1954 and 1973, Atanasoff was a witness in the legal actions brought by various parties to invalidate electronic computing patents issued to Mauchly and J. Presper Eckert, which were owned by computer manufacturer Sperry Rand. In the 1973 decision of Honeywell v. Sperry Rand, a federal judge named Atanasoff the inventor of the electronic digital computer.
