[firebones]

My HP-11C is going on 36 years old, flawless, and is reportedly Turing complete [1]. Echoing the @dbtc comment that there are likely many special purpose computers that are closing in on this.

[1] https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv020.c...

(If this is inaccurate about the 11c, and I'd love to hear why, then in a few years I'll see how my MacSE is doing. Just doing a casual assessment due to...late night.)

[7thaccount]

My HP-15c feels pretty great. I just bought one of the swissmicros calculators (the DM42) and it has something like an e-ink display with Corning gorilla glass and uses RPN of course. You can get an HP-11c clone too. They aren't cheap garbage either, but feel very solid and have the HP bugs fixed.

These aren't the kind of computer the author is talking about though. They're more concerned about writing and sharing information than performing mathematical calculations.