on November 15, 1971. It wasn't immediately available; in fact, it wasn't available to ordinary individuals until about 3 years later. I don't remember the exact date, but sometime in 1974 – about 41 years ago – I bought one of these magnificent parts. Mine looked just like the photo above, with a ceramic case and gold-plated (literally!) pins and lid. It was an expensive part when sold at retail – over $100, as I recall. At the same time, I bought a kit from some long-gone company. It was a bag of parts and a schematic; the entire kit had to be wire-wrapped. The schematic was the key bit. I had never designed anything like a microprocessor before, and having a schematic was mighty comforting. There was also a PROM (programmable read-only memory) with a small test program. I put the thing together in a single evening, staying up until quite late to do it. The “input” was a set of four toggle switches and a momentary push button; the “output” was four LEDs. I fired it up, and it worked – first try! Then I spent weeks understanding what I had built, and what it could do.
After exhausting the things I could do with a 4004 (they were ... not very powerful), I then built an 8008 kit, an 8080 kit, and finally tried my own hand at designing with a Z80 board, a Motorola 6800, a Mostek 6502, and even a Motorola 68000. Somewhere along the way I also built a bit-slice machine, 16 bits wide based on four AMD 2901s. The 4004 launched all that learning for me, and, in a significant way, launched my career.
Happy birthday, little 4004!