The Slide Rule: A Computing Device That Put A Man On The Moon. "For generations of engineers, technicians and scientists, the slide rule was an essential part of their daily lives. Until, all of a sudden, it wasn't. In 1972 Hewlett-Packard came out with the first handheld electronic calculator. Practically overnight, the slide rule had become obsolete."
Huge PICKETT N1010-ES Trig Classroom Display Advertising Slide Rule - 7 Feet/84". Every student needed their own slide rule and our teacher instructed us on their use with a classroom sized rule. This was before Hewlett Packard (HP using Reverse Polish notation or RPN) and Texas Instruments (TI using Polish notation) began marketing their new hand held calculators by the 1970s.
In December of 1972, TI files a patent application for the hand-held calculator with the inventors listed as Jack Kilby, Jerry Merryman, and James Van Tassel. HP introduces their first pocket calculator, the HP-35, the world's first pocket calculator with scientific (transcendental) functions. Slide rule sales plummet.
29 Times Tumblr Made "Harry Potter" Fans Cry All Over Again
Early special-purpose analog computers were the astrolabe of the Middle Ages, the slide rule, the curvimeter and planimeter, and the harmonic analyzer. In World War II, analog computing mechanisms were of great importance for gunfire control on warships.