The History Of The Calculator

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Business Calculator: The Electronic Age

The story of the electronic calculator really begins in the late 1930s as the world began to prepare for renewed war. To calculate the trigonometry required to drop bombs 'into a pickle barrel' from 30,000 feet, to hit a 30-knot Japanese warship with a torpedo or to bring down a diving Stuka with an anti aircraft gun required constantly updated automated solutions.These were provided respectively by the Sperry-Norden bombsight, the US Navy's Torpedo Data Computer and the Kerrison Predictor AA fire control system.

All were basically mechanical devices using geared wheels and rotating cylinders, but producing electrical outputs that could be linked to weapon systems.

During the Second World War, the challenges of code-breaking produced the first all-electronic computer, Colossus. But this was a specialised machine that basically performed "exclusive or" (XOR) Boolean algorithms.

ENIAC: less processing power than a non-smart phone.

However, it did this using hundred of thermionic valves as electronic on/off switches, as well as an electronic display.

The application of this technology to the world's first general calculating computer had to wait until 1946 and the construction of the ENIAC (Electronic Numerical Integrator And Computer) as a completely digital artillery firing table calculator also capable of solving "a large class of numerical problems", including the four basic arithmetical functions.

ENIAC was 1,000 times faster than electro-mechanical computers and could hold a ten-digit decimal number in memory. But to do this required 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed around 27 tonnes, took up 1800 square feet of floorspace and consumed as much power as a small town. Not exactly a desktop solution.

Valve and Tube Calculators

Electronic calculating for the office had to wait on the miniaturisation of valves and the development of solid state transistors.

Photo of ANITA
ANITA: First desktop all electronic calculator.

The first step was seen in 1961 with the arrival of ANITA (A New Inspiration To Arithmetic/Accounting). This was the world's first all-electronic desktop calculator and it was developed in Britain by Control Systems Ltd., marketed under its Bell Punch and Sumlock brands.

ANITA used the same push button key layout as the company's mechanical comptometers, but these were the only moving parts. All the rest was done electronically, using a mix of vacuum and cold cathode 'Dekatron' counting tubes.

The illuminated 12-place display was provided by 'Nixie' glow discharge tubes. From 1962, two models were marketed; ANITA Mk. 7 for continental Europe and the Mk. 8 for Britain and the rest of the world, with the latter soon becoming the only model. These early ANITAs sold for around £355 ($1,000), equivalent to around £4,800 ($8,000) in today's money.

Nevertheless, as the only electronic desktop calculator available, tens of thousands of ANITAs were sold worldwide up to 1964, when three new transistorised competitors appeared; the American Friden 130 series, the Italian IME 84, and the Sharp Compet CS10A from Japan.

Transistor Age Calculators

Friden calculator
Friden calculator: First CRT display.

None of these were functionally superior to ANITA, nor cheaper (the Sharp CS10 cost around $2,500 in 1964) but their all-transistor designs opened the floodgates to a new wave of electronic calculators.

These came from the likes of Canon, Mathatronics, Olivetti, SCM (Smith-Corona-Marchant), Sony, Toshiba, and Wang.

Four of these Beatles-era transistorised calculators were especially significant, including Toshiba's "Toscal" BC-1411 calculator, which was remarkable in using an early form of Random Access Memory (RAM) built from separate circuit boards.

The Olivetti
Olivetti: Programma 101: World's first PC?

The Olivetti Programma 101 introduced in late 1965 was an elegant machine that won many industrial design awards. It could read and write to magnetic cards and display results on its built-in printer.

As a desktop electronic calculating machine that was programmable by non-specialists for individual use, the Programma 101 could even claim to be the first personal computer.

From behind the Iron Curtain the same year emerged the ELKA 22 designed by Bulgaria's Central Institute for Calculation Technologies and built at the Elektronika factory in Sofia.

Built like a T-64 tank and weighing around 8 kg, this was the first calculator in the world to include a square root function.

The Texas Cal Tech
Texas Instruments 'Cal Tech': shape of things to come. Photo credit: Texas Instruments

All electronic calculators to this point had been bulky and heavy machines, costing more than many family cars of the period.

However in 1967, Texas Instruments released their landmark "Cal Tech" prototype, a calculator that could add, multiply, subtract, and divide, and print results to a paper tape while being compact enough to be held in the hand.

A new chapter in the calculator story was opening...

Continue on to part 2 of our story of the history of the calculator, where we look at the microchip age and the virtual age.

Written by Nick Valentine

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Last update: 06 September 2018

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