1964 · All-Transistor Desk Calculator · Work 925 of 1,871
The office of a textile wholesaler in Osaka on a summer morning, on a steel desk a grey metal calculator forty-three centimetres wide, its light grey sloping key plate set with ten columns of round keys in alternating white and dark slate blue, larger cream, red and dark blue keys at the right, every key plain, smooth and unmarked, at the back behind a dark glass window a long row of small tubes glowing soft orange, along the front a round red button and a row of small black knobs, a hand in a black cotton oversleeve at the keys, through the window a small new car parked in the sunny street.
What it was used for
According to the Information Processing Society of Japan the Compet CS-10A electronic desk calculator cost 535,000 yen, "comparable to a popular automobile at that time", and was thus very expensive to buy for personal use; the IPSJ credits its popularity to fast operating speed and quietness compared with mechanical calculators. Nigel Tout writes, on information provided by Sharp Corporation, that demand grew so fast that monthly production of 300 units could not keep up. For scale: in 1965 only 4,300 electronic calculators in all were produced in Japan.
What was new
The arithmetic was all-transistor, the display was not: the arithmetic unit used germanium semiconductors - the IPSJ counts 530 transistors and 2,300 diodes among some 4,000 parts - while the 20-digit display was made of Nixie tubes. Sharp claims not "all-transistor" but "the world's first electronic desktop calculator using all-transistor diodes", that is, the circuit technique; the IEEE milestone of 2005 makes no priority claim for the CS-10A. Nigel Tout counts 4 contenders for the title of first all-transistorised desk calculator: CS-10A, Friden 130, IME 84 and Mathatron. The detour there is the barb: the laboratory founded in 1960 was to build a large computer, and the objective was switched to a small calculator usable like an abacus, whenever, wherever and by whomever.
What the sources leave open: The component counts count different things: the IPSJ gives 530 transistors for the machine, the Semiconductor History Museum of Japan up to 350 for the arithmetic unit; the Smithsonian gives some 5,000 components for early versions against about 4,000 at the IPSJ. The month is open: announced 14 May 1964 (Smithsonian), introduced June (Old Calculator Museum) or July 1964 (Tout). Total units and named users are not documented.