The history of computing, both hardware and software, is punctuated by patent wrangles. One of the most bitterly contested hinged on a meeting that took place on June 14, 1941 when John Mauchly went to Iowa City to see John Atanasoff and his ABC computer.
The two men later presented contrasting accounts of the visit.
Atanasoff claimed that Mauchly "expressed joy" at seeing parts of the ABC work out some simple arithmetic. Mauchly stated, "I found that although he used valves and did do it relatively cheaply he lost most of the advantage because he wasn't doing it fast."
The difference in viewpoint over the visit is striking. Atanasoff said Mauchly was fascinated. Mauchly said it was a waste of time.
Whatever the truth it is likely that both Atanasoff and Mauchly had good cause to regret the short visit for many years as it became a key issue in which of them was credited as the inventor of the computer. The court ruled that ENIAC was derived from the ABC and therefore that Atanasoff was the inventor of the digital computer.
A working ABC replica
ABC - Atanasoff-Berry Computer