From coffee grinders to core dumps: the history of the calculator

You could tell the engineering students with the HP calculators;  their shirts pulled out of shape by carrying the bulky device in their top pockets, their tussled appearance from sleeping later and working less, their unruffled appreciation of the higher calculus.

It was a source of envy.

They smiled at matrices, they laughed at integrals.  I learned a fiendish ability at mental arithmetic.  I could manipulate three-dimensional integrals in my head.  I was tough.  And the calculators did make their owners somewhat lazy. 

Still, it was Gottfried Wilhelm Von Leibniz who said, in 1685, "For it is unworthy of excellent men to lose hours like slaves in the labour of calculation which would safely be relegated to anyone else if machines were used."

He knew what he was talking about.  In 1674 he built the first prototype of his Stepped Reckoner, a mechanical adding calculator designed to perform the four core functions of addition, subtraction, multiplication and division.  At its heart was the Leibniz Wheel which was a cylinder with nine bar-shaped teeth of incrementing length parallel to the cylinder’s axis.  As brilliant as he was, his war with Isaac Newton left him bereft, unappreciated and impoverished.

The dream to automate computation prevailed.  Too much of navigation required repetitive numerical calculations.  The invention of logarithms, allowing the conversion of multiplication into arithmetic, required vast tables and sums.  Inventions, such as the slide rule by William Oughtred in 1633, were simply aids to memory and speeded up the process, but didn’t automate it.

Some movie buffs may remember that, in the movie Apollo 13, the best available technology for course corrections on 11 April 1970 was feverish computation on slide rules.

The Thomas Machine, or Arithmometer, was a four-function mechanical calculator based on the Leibniz model.  It was sold for more than 100 years, between 1820 and 1930, inspiring clones across the world.  Other developments took Leibniz’s nine stepped drums and replaced them with variable-toothed pinwheels.  Still others sought to develop keyboards to make computation a bit more natural.   

Incremental improvements led to calculators that stored a limited amount of information mechanically and handled carries.  The number of digits in a number was a limiting factor since each digit required its own set of drums.  As late as the 1960s, when my father studied engineering at the University of Cape Town, they were using these mechanical “coffee grinders” to churn out calculations.  This ensured that engineers got some exercise while they undertook higher mathematics.

The first electrical calculators simply replaced the mechanical winding with an electric motor.  They were noisy, smelly, expensive and incredibly heavy; so, even though they were introduced in the early 1900s, it wasn’t till the 1940s that they started making an appearance on every desk.

In 1961 Sumlock Comptometer in England introduced the first electronic calculator, the ANITA (A New Inspiration To Arithmetic) and ended the 338-year era of mechanical adders.  ANITA used vacuum tubes and was quickly replaced by the transistor-based Friden.  Sharp’s 1964 all-transistor weighed in at an impressive 25 kilograms and cost $2,500.  A long, long way away from calculators so tiny they can be installed in digital watches, and at prices so low they’re given away at conferences.

Jack Kilby, at Texas Instruments, is often credited with inventing the first pocket calculator in 1967, but it was quite some time before the names caught up with events.  Many of the original “portable” devices were anything but.

In 1972 HP released their HP-35, the world’s first scientific function calculator.  This one did fit in a shirt-pocket.  Slide-rule sales plummet.  Prices continued to plunge until electronic calculators were almost universal.  By 1975, in a by-now familiar refrain, teachers demanded that calculators be banned from classrooms for fear that students wouldn’t learn maths.

The biggest innovation came in 1976 when stability issues with liquid crystal displays (LCDs) were ironed out.  Using significantly less power, these devices improved battery life from hours to days.  I’ve been using the same Sharp scientific calculator almost daily, on the original set of batteries, since I first got it for school in 1987.

By 1978 calculators had dropped below $10 per unit.  Symbolic calculations were introduced by HP with the HP-28 – which could solve quadratic equations - and who, along with Texas Instruments, were gaining a major reputation amongst number-crunchers for innovation and design.  Many HP sales reps were reported to begin product demonstrations by slamming their calculators on the floor.

The HP-48 series was the one that I lusted after; with its graphing functions and serious symbolic computation ability.  It was a mystery why both HP and Texas Instruments chose to reduce the reliability and complexity of their designs; HP dramatically in 2002 declared that they were to stop making calculators at all.

Yet it is not so surprising.  Desk-top computers were also taking over and can do significantly more than calculators.  Perhaps, though, hand-held calculators will stage a resurgence as cell-phones become ever more complex and reliable.  Soon teachers will be complaining once more as students place tiny communications devices on their desks and use them to answer their entire examination papers in less than a minute.

And those, such as I, working away with pen and paper lust after them out of the corner of our eyes.