I'm thinking of how most new laptops have given up the optical disk drive, and things like the nimo tube [0] or many other examples one could give of obsolete [1] technology.<p>[0] https://news.ycombinator.com/item?id=23076589<p>[1] adj. no longer produced or used; out of date.<p>P.S.: What is the go-to reference for human technology? Just because a technology becomes obsolete (which IMO has a negative connotation) it shouldn't mean it should be forgotten and the principles used in ingenious designs can't be reused. Best I can find is museums or history of technology books, but no catalog.
Cesium Beam Atomic Clocks - They can keep time accurate to a second in 10,000 years, but the tubes themselves only last 5-7 years of service. Typically they draw on the order of 100 watts.<p>Obsoleted by<p>Cesium Vapor Cell Atomic Clocks have a sealed cell of cesium vapor, are probed with a semiconductor laser modulated with microwaves, and draw 1/8 watt in a tiny package, and should last essentially forever.
It can be hard to find an automotive shop with a working OBD1 interface and emissions setup. Luckily that's no longer an issue in some places.<p>Certain replacement fluorescent ballasts are already hard to find, and that will only accelerate as LEDs replace other fixtures.<p>Computer-designed flat and microantennas with interesting geometry seem capable of replacing much bigger antennas. Maybe the shape of TV antennas for sale shows that's already complete in consumer electronics.
> P.S.: What is the go-to reference for human technology?<p>You should repost that paragraph as its own ask HN. That would be a fascinating set of references.<p>On the desk of a mechanical or chemical engineer I once saw a book containing common or basic machines.