A QWERTY Calculator

In 1992 I was a science student at the Australian National University in Canberra. Physics laboratory classes are difficult enough at the best of times, but when one wrong key press ruins a lengthy calculation of a formula (watch those significant figures!) it can be extremely frustrating and costly on marks.With only single value memory storage, my high school scientific calculator just wasn’t up to the task.

The in-thing amongst students in those days was the HP48 series of programmable calculators. It could do symbolic math, matrix algebra and even hook up to a PC. The HP48 was also very expensive, beyond my budget.

At Phillips Photographics, a Canberra shop which stocked a big range of calculators and their ilk, I saw my dream machine – the HP200LX. This clamshell palmtop device was a full MS-DOS computer, QWERTY keyboard, monochrome CGA screen and 512KB memory. It didn’t come with mathematics software to rival the HP48, but you could probably install it. I could imagine myself working anywhere and everywhere. I wanted it and couldn’t afford it.

Instead I bought a Sharp PC-E500 Pocket Computer. Instead of an mini IBM-compatible PC like the HP200LX, this was like a smaller version of my old Microprofessor or Amstrad. It run a BASIC programming language interface, had a QWERTY keyboard, but with a scientific calculator pad to the right – virtually the same as my existing Sharp calculator. The PC-E500 had a 4 line ( x ) monochrome LCD screen and about 32KB of shared storage and program memory.

The PC-E500 came with various engineering, scientific and mathematical programs preinstalled that made it genuinely useful during my studies. Data plotting, numerical integration, the periodic table all came in handy, as did the ability to check my matrix inversions – an otherwise lengthy process fraught with errors.

It was also possible to extend the PC-E500’s capabilities by writing your own programs in BASIC. I often found myself missing my electronic piano while travelling, so I wrote a program to turn the PC-E500 into a musical keyboard, although the results were not particularly spectacular.

While the PC-E500 worked well as a sophisticated calculator, there were two features that it lacked to make it truly useful as a travelling computer. One was any basic wordprocessing capabilities. The other was the ability to transfer data to a PC.

Both were actually possible. I could have written a program to take notes, although memory limitations would be very restrictive. The owner of Phillips Photographics actually sold handmade cables to connect the PC-E500’s proprietory serial port to a PC, but I could not afoord the extra $100 he charged. The plans are now available on the internet.

Without the ability to transfer data from the pocket computer there was no way of using the results of calculations in my reports. According to the PC-E500’s manual a couple of printers were available, but they were likely expensive and not suitable for my purposes.

So my search for my perfect electronic travel companion continued.

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