On this day in 1932, Robert Heath Dennard was born in Texas. He worked at IBM, and in the mid-1960s he came up with a way of storing a bit of computer memory that has been under the fingers of nearly everyone since.

Here's the clever bit: before him, a bit of fast memory took six transistors, or a tiny ferrite ring threaded by hand. Dennard's cell is a single transistor and a capacitor. The capacitor holds a little charge, which is the one or the zero; the transistor stands guard at the gate, letting the charge in or out when asked. The catch is that charge leaks away in milliseconds, so the whole array has to be read and written back thousands of times a second, quietly, forever. That is the dynamic in dynamic random-access memory. Most memory is not a stone tablet at all. It is a bucket with a slow drip, and a very patient person topping it up.

He also gave his name to the scaling rules that guided chipmaking for decades, though he was, by all accounts, a modest man about it. He died in 2024. Spare a thought as well for the core-memory weavers whose work his invention replaced: those tiny lattices were strung by hand, and they were beautiful.