Looking inside a 1970s PROM chip that stores data in microscopic fuses (2019)

Yeah... I remember designing these into circuit boards. They were much cheaper than EPROMs, so we did development with EPROMs and production with PROMs.

And then we desoldered and replaced all the PROMs when we found a problem.

I remember knowing about these at uni and then learning about reprogrammable UV erased PROM and thinking the same magic faries who do the link fusing probably had tiny soldering irons to fix them in the reprogrammable ones (we said if you let the magic fairy smoke escape from your circuit board it wasn't surprising it stopped working...)

$70 for 1024 bits is the part that lands. The 33x33 array with an extra row and column is a neat wrinkle.