History of the calculator: the microchip age and virtual age

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Calculators Now: The Virtual Age

By 1980, pocket and desktop calculators had essentially reached the forms we recognise today; compact in form, using single chips and LCD displays, operated via silicone membrane or dome switch keyboards, powered by solar cells or button batteries and capable of a wide range of functions.

Pocket calculators had also become very cheap, with some selling for as little as $1.99. Before long, companies were starting to give pocket calculators away as freebies, much as USB memory sticks are today.

By the eighties, the market was becoming saturated. Since it was hardly possible for calculators to become less expensive, they could only find new buyers by acquiring new forms and functions.

Pocket Computers

The decade had barely begun when one possible route for calculator evolution appeared in the form of the amazing Sharp PC-1210 and PC-1211 'pocket computers' and their Radio Shack equivalent, the Tandy TRS-80.

Tandy TRS-80
Tandy TRS-80: calculator meets computer.

By the standards of the day, these were astonishing devices; combining a calculator with a full QWERTY keyboard and 24-digit alphanumeric dot matrix LCD. They were programable in full BASIC language and, via a cassette recorder input/output and docking into a mini printer, these devices could perform almost the full range of computer functions.

However, there was no way of driving a full CRT monitor, which was a major reason, along with lack of network connectivity, why the pocket computer proved to be a technological dead-end.

Already, it was possible for the prescient to discern a faint looming threat to the calculator: the increasing prevalence, adaptability and functionality of personal computing.

However, that was still a full decade away and for the moment, the calculator was still the ultimate form of computing for most. Besides, calculating still had one or two more major evolutions up its sleeve.

Graphing Calculator

Casio fx-7000G
Casio fx-7000G: the graphing calculator arrives.

One was the development of the graphing calculator, a pocket sized device that could plot graphs, solve simultaneous equations, and perform numerous other tasks with algebraic variables. Graphing calculators are also programmable, allowing the user to create customized scientific, engineering and educational applications.

By the mid-1980s, Casio was vying with Sharp, Texas and HP for dominance of the calculator market and it was they who developed the world's first graphing calculator, the Casio fx-7000G in 1985.

The fx-7000G was relatively primitive in having only an eight line dot matrix B/W display and less than half a kilobyte of programming memory. However, it proved the concept with an enlarged display and the capability to handle 82 scientific functions along with manual computation for basic arithmetic along with a programming mode.

Like many of the more serious calculators, it used Reverse Polish Notation (RPN) where the operators are entered after the operands. So where a basic calculator would use 4, x, 5, = [20] the RPN would use 4, 5, x, key pushes. RPN has been proved to deliver faster calculations with fewer errors.

Hewlett Packard soon followed suit with its own range of graphing calculators, starting with the HP-28 series of 1986-88.

The HP-28
HP-28 graphing calculator: two-in-one design.

These were capable machines, sporting a flip-open "clamshell" case that paired an alphabetic keypad with a typical scientific calculator layout, along with a 137x32 LCD dot matrix display, usually displaying four lines of information and boasting four times as much memory as the Casio.

However, a design omission that had seemed insignificant in 1986 had by 1988 become a serious flaw, the lack of a computer interface for uploading or downloading data. This was addressed on the HP-48 series from 1990 onward.

The original HP-28C had a suffix denoting that it featured continuous memory. However by 1988 that was no longer remarkable, since it had become common on all serious scientific and business calculators. So in the late 1980s, HP calculators were classed "S" for Scientific, "B" for Business, and, from 1993, "G" for Graphic.

Vertical Integration

The Calculated Industries ElectriCalc Pro
Calculated Industries ElectriCalc Pro: a calculator for electricians. Photo credit: Mark Bollman

Calculators were starting to go vertical - using flavored designs to appeal to specific market niches. This trend was also seen in the emergence in the late 1980s of a new player, Calculated Industries.

CI produced designs tailored to specific trades and professions. Their first machine, the Loan Arranger, was a simple to use loan amortization calculator marketed to the real estate industry.

CI has gone on to develop a wide range of other specialty calculators aimed at financial planners, contractors, carpenters, plumbers, radio and television broadcast professionals, educators, electricians, machinists, and even quilters.

Market segmentation was also seen when Texas Instruments produced its own line of graphing calculators, starting with the TI-81 in 1990.

Not only were these calculators squarely aimed at the educational market but increasingly at different segments of it.

The Texas TI-81
Texas TI-81: optimized for students.

So while TI-80 and TI-73 were aimed at junior students 10–14 years of age, other models such as TI-85 and TI-86 were aimed at senior students, with features like calculus.

More modern graphing calculators produce color outputs and animated and interactive 2D and 3D drawings of math plots, handling animated algebra theorems and preparation of documents incorporating results.

Many can function as data loggers taking inputs from digital thermometers, pH gauges, weather instruments, accelerometers and other sensors, with WiFi or other communication modules for monitoring, polling and interaction with teacher.

This has given the calculator a guaranteed presence in high school classrooms and even in exam rooms where they were formerly disallowed.

As the 80s gave way to the 1990s, new threats emerged to the calculator.

Enter Mobile Devices

The Personal Communicator
BellSouth/Simon Personal Communicator: sign of things to come.

Along with the increasing prevalence of PCs and laptops, there was the advent of smarter mobile phones.

The first hint of what was to come was delivered by the BellSouth/IBM Simon Personal Communicator of 1993.

This was a cell phone (still very chunky by today's standards) with added Personal Digital Assistant (PDA) functions including email, address book, calendar - and calculator.

In the same year, Apple's Newton PDA first made its appearance, also with a calculator function.

It was soon followed by longer-lived Palm and Handspring PDAs. By now the calculator had been relegated to the third device in your pocket, bag or case.

The Nokia Communicator
Nokia Communicators: 1990s-style smartphones.

The threat became still more explicit in 1996, with the launch of Nokia's 9000 Communicator, a remarkable 'bells and whistles' device that bundled mobile phone with PDA functions and internet connectivity to produce one of the world's first true smartphones.

In 2000, the Ericsson R380 did the same thing in a more compact package, confirming the trend.

The mid-2000s unleashed the deluge: the Blackberry phone (2003), followed by the touchscreen Apple iPhone (2007) and a host of Android and Windows Phone imitators. From 2010 and the launch of the Apple iPad, the idea of tablet computing first essayed in 1993 had come to fruition.

All of these devices had calculator functions embedded, not as hardware add ons but virtually in software, either as part of the original Operating System (OS) or as a downloadable 'plug in' application. And apps are unlimited - even graphing calculators or industry specific models can be emulated in software.

The CalcXT app
CalcXT app for Apple iPad. Photo credit:

Yet the world's stores and online portals still supply well over 250 different models of calculator, ranging from a couple of dollars to more than $700, for a fully featured graphing calculator.

The Future

Four main factors are keeping the calculator alive. One is that designs have been successively optimised to purpose, producing a level of function and capability that even tailored apps struggle to emulate. The second is the high price of current smartphones and tablets while the third is that some people just find it easier, quicker and more precise to operate a physical device than a touchscreen.

The Desk Calculator
Desk Calculator: Back to the Future? Photo credit: Tsiakkas Office Solutions

Last, and arguably most important, 'dumb' calculators have over the decades earned a place in school and university exam rooms that remains closed off to 'smart' tablets and phones for the foreseeable future.

The desktop calculator, too, soldiers obstinately on, keeping its place in the office by dint of its ergonomic advantages and 'print as you go' function.

It would be ironic indeed if the humble desktop adding machine remains standing after the last sophisticated pocket calculator has found its glass case in the Museum of Doomed Technologies.

What do you think the future holds for the calculator? Which calculators have you used during your lifetime? Leave your comments below.

Written by Nick Valentine.

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Last update: 24 March 2014

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