Paul Eggert wrote on 1998-10-11 00:25 UTC:
Adjusting clocks backwards is just a figure of speech to explain DST switches to the general population without introducing proper notation.
Sorry, you've lost me. Adjusting clocks backwards is a figure of speech? In a couple of weeks, I'll be wandering over my house, office, and car manually adjusting dozens of dumb localtime clocks backward. On that day it certainly won't feel like a figure of speech. :-)
I think it is time mankind should advance the state of the art on household clocks a bit: Instead of wandering around to turn them back, you should be able to program them such that tonight they will go through the hours 1, 2A, 2B, 3, etc. Then DST switching becomes an exercise of inserting and deleting leap hours into the time scale, removing the ambiguity of the repeated hour. Most clocks have integrated circuits, therefore this functionality would cost practically nothing to add. If you know a clock manufacturer desperately looking for new features to add, feel free to forward this patent-free idea. Unfortunately, the only self-adjusting clocks that I know of are computers and radio clocks. Actually thinking about it, there is a neat way of encoding hour 2A in a distinguishable way even on "analog" clock displays: Just stop the motion of the hour pointer for 60 min during hour 2A, and it will be immediately recognizable whether you are in hour 2A or 2B (except perhaps for the first few minutes of the hour, where the smaller pointer hasn't moved yet much during hour 2B). Markus -- Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK email: mkuhn at acm.org, home page: <http://www.cl.cam.ac.uk/~mgk25/>