Re: GPS is not this day and age
The ZX80 was a miracle of cost reduction. I was working in the labs of an electronics firm. One of the teams pulled one apart and "obtained" a circuit diagram. There was some head scratching understanding how it managed to work. I recall that rather than there being a couple of chips to scan the keyboard switches they used the processors upper address lines, presumably by having a bit of code that jumped to "funny" addresses that would light up the upper address lines.