[LEAPSECS] Schedule for success

Rob Seaman seaman at noao.edu
Sun Dec 21 15:58:42 EST 2008

Rather than speculating on each other's state of mind with words such
as "fundamental misimpression" (as in the thread below), it might be
helpful to focus on the actual questions asked.

Consider the iconic issue of timekeeping for trains, one of the
primary drivers for our current standard time zone system. Trains
clearly need to be synchronized with external clocks. Trains clearly
have some mechanism or set of procedures (imperfect or not) for doing
so. So they don't match the question asked.


On Dec 21, 2008, at 1:10 PM, Poul-Henning Kamp wrote:

> In message <m3prjlxz5z.fsf at lugabout.jhcloos.org>, James Cloos writes:

>>>>>>> "Warner" == M Warner Losh <imp at bsdimp.com> writes:


>> Warner> You are under the fundamental misimpression that all

>> systems are

>> Warner> or can be upgraded every 6 months. That simply isn't

>> possible

>> Warner> for a large class of systems.


>> But how many of the systems which do not have such a regular update

>> procedure in place care about time?


> Everything relating to the power-grid load/supply distribution,

> that means control of power-plants, transformers and switching

> stations. (The "supergrids" people dream about will require better

> than 6msec autonomous holdover time precision for 24+hours at all

> control points).


> Everything relating to modern train control and management.


> Everything relating to air traffic control.


> Shiping control systems in narrow corridors (The Channel, The Great

> Belt etc.)


> Military early warning systems.


> etc.

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