Though mobile devices and Apple Silicon have seen ARM-64 explode across the world, there’s still decent odds you’re reading this on a device with an x86 processor — the direct descendant of the world’s first civilian microprocessor, the Intel 4004. The 4004 wasn’t much good on its own, however, which is why [Klaus Scheffler] and [Lajos Kintli] have produced super-sized discrete chips of the 4001 ROM, 4002 RAM, and 4003 shift register to replicate a 1970s calculator at 10x the size and double the speed, all in time for the 4004’s 50th anniversary.

We featured this project a couple of years back, when it was just a lonely microprocessor. Adding the other MSC-4 series chips enabled the pair to faithfully reproduce the logic of a Busicom 141-PF calculator, the very first to market with Intel’s now-legendary microprocessor. Indeed, this calculator is the raison d’etre for the 4004: Busicom commissioned the whole Micro-Computer System 4-bit (MCS-4) set of chips specifically for this calculator. Only later, once they realized what they had made, did Intel buy the rights back from the Japanese calculator company, and the rest, as they say, is history.

Since its history, it belongs in a museum– and that’s where this giant, FET-based calculator is going. If you happen to be in Solothurn, Switzerland, you’ll be able to see it at a new history of technology exhibit opening at the Enter Museum in 2026. Do check out the write-up and links at 4004.com if you want to learn about this important piece of human history.

We had to specify “first civilian microprocessor” at the start of this article because the US Navy beat them to the punch by a whole year, and kept it secret until 1998. There’s something very 1970s about the fact that top-secret US military technology was reinvented for a Japanese calculator within a year. It honestly makes [Federico Faggin], the man credited with the design, seem no less visionary than when we thought he was first out of the gate.