The Therac-25 Incident (2021)

My "favorite" part:

>One failure occurred when a particular sequence of keystrokes was entered on the VT100 terminal that controlled the PDP-11 computer: If the operator were to press "X" to (erroneously) select 25 MeV photon mode, then use "cursor up" to edit the input to "E" to (correctly) select 25 MeV Electron mode, then "Enter", all within eight seconds of the first keypress and well within the capability of an experienced user of the machine, the edit would not be processed and an overdose could be administered. These edits were not noticed as it would take 8 seconds for startup, so it would go with the default setup

Kinda reminds me how everything is touchscreen nowadays from car interfaces to industry critical software

And we have a concept, optimistic updates, for making the ui look responsive while the updates happen in the background and reconcile later. I can only hope they know when not to use it.

   Try quickly typing 1+ 2 + 3 into the iOS 11 Calculator (reddit.com)
   886 points by danso on Oct 24, 2017 | hide | past | favorite | 480 comments

https://news.ycombinator.com/item?id=15538666

...this _exact_ same failure mode in a "less" critical domain (eg: literally your most frequently used "pocket calculator"), unless you're using the calculator for Important Things(tm).

Optimistic updates should almost always be paired with some sort of indicator showing if/when a value has actually been persisted. In practice this is rarely implement. Even failures are often not shown and value rolled back. (Making it a very optimistic update indeed)