An ALU As A Desktop Calculator Has Stunning Style From Days Gone By

Those of you with an interest in microcomputer history will know that there is a strong crossover between the path of electronic calculator evolution and the genesis of the integrated CPU. Intel’s 4000 was famously designed for a calculator, and for a while in the 1970s these mathematical helpers were seen as the wonder of the age. [Simon Boak]’s calculator is a curious throwback to that era, as it’s not a decimal calculator as we’d know it but a hexadecimal device that simply computes using the functions of the famous 74181 ALU chip.

An ALU, or to give it its full name an Arithmetic Logic Unit, is a component of a CPU with two inputs and one output that can perform any of a range of binary functions upon the two inputs and return the result on the output. This calculator has two of them for eight bits of raw adding power, with a hexadecimal keypad for setting the inputs and a set of 7-segment displays for showing the results. It’s housed in an achingly retro folded sheet metal console case with wooden end pieces that would have graced any engineer’s desk with pride back in about 1975. We may not need one, but we really want one!

If the 74181 is a mystery to you then fear not, because chip master [Ken Shirriff] has produced some handy explanation work on its operation.

Thanks [Ted Yapo] for the tip.

Learn To Count In Seximal, A Position Above The Rest

Believe it or not, counting is not special. Quite a few animals have figured it out over the years. Tiny honeybees compare what is less and what is more, and their brains are smaller than a pinky nail. They even understand the concept of zero, which — as anyone who has had to teach a toddler knows — is rather difficult to grasp. No, counting is not special, but how we count is.

I don’t mean to toot our own horn, but humans are remarkable for having created numerous numeral systems, each specialized in their own ways. Ask almost anyone and they will at least have heard of binary. Hackaday readers are deeper into counting systems and most of us have used binary, octal, and hexadecimal, often in conjunction, but those are just the perfectly standard positional systems.

If you want to start getting weird, there’s balanced ternary and negabinary, and we still haven’t even left the positional systems. There’s a whole host of systems out there, each with their own strengths and weaknesses. I happen to think seximal is the best. To see why, we have to explore the different creations that arose throughout the ages. As long as we’ve had sheep, humans have been trying to count them, and the systems that resulted have been quite creative, if inefficient.

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