The article covers the enjoyable experience of getting networked computers to all agree on a single monotonic clock time. That got me wondering - does there exist a commodity, high-precision, high-reliability hardware clock that can be plugged into a computer to give it super-accurate timekeeping?

(TBH, I'm pretty sure the answer is no - if you want super-accurate time, I think you buy your own very expensive NTP server [1].)

[1] https://www.masterclock.com/master-clock-products.html