ryemac3:
I have to wonder, back in the day, they must have been using 8-bit micros.
Do you care about the history of computers and computation at all?
Last night I watched "The Imitation Game" - and that comment - as innocent as it might be - grates on my nerves.
Mainly because it says that all you are doing here is making a bunch of grand assumptions as to what a calculator (not even a computer!) could do in the 1960s and 70s - what it was composed of, and how it functioned - without even doing the minimum amount of research possible using the internet the machine in front of you that is the grand result of that research and development of the past!
Please! If you care at all about this subject - do the research! It's beyond fascinating! It covers vast swaths of history and time periods and invention in an almost unimaginable way! Mankind has been speculating on the concept of machines that could imitate human action and thought for thousands of years, but it has only been in the last 50 or so years that we have managed to create a machine - indeed, understand how it could possible be so - that could think in some manner like we do.
We virtually owe most all of this to one man. Ok - being honest, we owe it at least to three men - these people, of which one is well known today, and the other two still languish at least outside of mathematical circles - put forth the understanding and insights which allowed for the understanding that machines could manipulate symbols - and not just numbers - which is the ultimate basis for all of computer science. Even so, it was only one of those individuals who had the insight to come up with that machine, and then take it from the abstract to the real, and prove that such a limited version (for his universal machine lived in the realm of mathematics, where its memory was defined as "infinite") could be useful. Unfortunately, his achievement wouldn't be released to the public until the 1970s (it was classified) - and a full apology wouldn't be given until 2013. But I digress.
8-bit CPU? Silicon?
At best - you were looking at a completely transistorized calculation machine - that is, discrete transistors. Oh, how I kick myself today over the destruction I wrought to one of those devices! It had been given to me as "junk" by my boss at my first software development job - I was 18, and took it apart. It had a nixie tube display, but there were no integrated circuits to be found. The entire thing inside was crammed full of individual transistors. I tossed that away like so much useless trash to me. There was one part I didn't understand - even after I took it apart - and wouldn't understand until a few years later - and then I realized what I had destroyed...
Inside was a metal box - about the volume of a pack of cigarettes, maybe a bit more square and thinner (say 5 or 6 cm on a side). Two pairs of wires led into the box, and it was sealed air-tight. It was also very light-weight. I was curious - what could be inside that box? So, I went at it with the only tools I had - a hammer, a screwdriver, and a pair of cutters and pliers. I eventually got it open enough to see inside...what was that? A coil - of wire? One end connected to where a pair of wires went into - but connected to some kind of ceramic "nub" - the wire was silver, and made a coil of one or two loops - then back to another ceramic "nub", where the other pair of wire led out from. Strange, I thought - I had no idea what it was - but it seemed useless to me, so I tossed it. The only thing I kept from that calculator was the nixie tube display - and in the end even that was discarded over several moves of my household.
I only later learned what I had destroyed: A desktop calculator that had spanned three generations of technological know-how: Nixie tubes for a display, transistors for logic and calculation purposes, and finally - a wire delay line, for memory storage. Yes - that box with the coil of wire, was the memory storage system of the calculator. Those "ceramic nubs" were actually piezo tranducers with a (likely) nickel wire bonded to them, which would "vibrate" the wire with the bits which made up the number, and the other end would pick them up, reform them through some kind of amplication system, then feed them back thru the other end. Obviously, there was also some way to recall the number, and read it from the vibrating wire. It was contained inside a box, which likely had some kind of rare-gas atmosphere sealed inside to prevent corrosion, and maybe temperature fluctuations from hampering it's workings.
...and I had destroyed it.
I wish I had it for my small historical computer junk collection I have today; it would have been a great piece to have for it.
Sorry for the trip down memory lane - but maybe it shows you what kind of passion I have for these wondrous machines, and that what we look at today as microcontrollers and microprocessors - are so very, very advanced from those days (heck - so very advanced from the time when I got my first 8-bit computer in the 1980s!).
When you hold an Arduino in your palm - realize that what you are holding is something that would have been nearly unthinkable to have only 30 years ago. It certainly wouldn't have been thought to only cost the few dollars it does today (which, compared to 30 years ago, is a relative pittance given inflation). Have no doubts - the Arduino is a very advanced bit of technology. Have fun with it - create your calculator; but also realize that what you are doing is akin to taking a rocket engine and making it perform the role of a steam engine. Even so, steam engines are worth understanding in their own right - in order to help to understand where more advanced engines came from. So it is the same with computers and computation.
