The HP-35 - some history of the innovation that helped make it happen and how it got its name
In all, 100,000 HP-35’s (or more than 10× their estimate) were sold in the first year—accounting for more than half of the company’s total profits—and nearly 350,000 were sold over its three-year lifespan.
It would be difficult to overestimate how disruptive the HP-35 was. As Lewis Terman stated when he named it an IEEE Milestone in 1997: “[it] accelerated the pace of technological change and revolutionized the engineering profession.” Literally overnight the slide rule became obsolete; in July, 1976 the venerable firm of Keuffel & Esser manufactured the last slide rule made in America.
The Regency TR-1 radio may have been the first commercial handheld electronic device, but it was the HP-35 that first truly presaged the future of consumer electronics. The combination of state-of-the art ICs (then microprocessors), close attention to programming and carefully considered industrial design served as the model for nearly every handheld device since; everything from Mattel Electronic Football (1977), to the Gameboy (1989), to the Palm Pilot (1997), to the Nokia 1100 (2003), to even your current face-recognizing iPhone.