If you go back in computing history and search for the roots of personal computers you will for sure stumble across the HP 9100. However, most probably you will end up with the Olivetti Programma 101 which is recognized as the world’s first desktop computer commercially produced.
At the BEMA Universal Exhibition in New York in October 1965, Olivetti launched a programmable calculator fitting on a desk. In the era of huge mainframes that was revolutionary. As the HP 9100 it was built without integrated circuits or microprocessors. There are other similarities between those two calculators like the magnetic card reader. It looks like Hewlett Packard copied this and that from the Programma 101, at least they had to pay $900’000 to Olivetti due to patent infringements. If you want to learn more details about the Programma 101 have a look at Olivetti Programma 101 “Perottina” and The incredible story of the first PC. There is even a simulator for this interesting machine.
While looking for some information about the Programma 101 I stumbled across an article about it in Business Week published on October 23, 1965. That’s actually my birthday, a funny coincidence 🙂