Re: Torino meeting and implications of international time UT1
On Thu, Jun 05, 2003 at 10:38:03AM -0700, Steve Allen wrote: On Thu 2003-06-05T17:46:38 +0100, Markus Kuhn hath writ: William Klepczynski: In safety-critical navigation systems, leap seconds will over time cause catastrophic system failures that will cost many lives. This long-term risk should justify even considerable one-off expenses to fix permanently the problem of a commonly used non-uniform precision timescale. I rebut that any system whose designers cannot implement a specification as clearly spelled out as the current scheme for UTC has much worse things to worry about than leap seconds. You presume that such systems are designed by folk who even know that there is something to be careful about... In my experience the vast majority of people, including intelligent hardware and software engineers, don't grok the nuances of UTC --- even to the extent of not realizing the existence of leap seconds. I can easily envision some complex system whose overall design and manufacture was exquisite except for the simple detail that the designer failed to understand that the reference time signal they were feeding as input was _not_ an unsegmented time. But it is the official time broadcast from the folk who maintain our atomic clocks, I can hear our belatedly enlightened designer moan. This is more of an argument for better education to the public, especially the technical sectors of the public, than an argument to abolish leap seconds. Or perhaps a good argument for having hybrid time signals (some form of TI and some form of UT), which would make anyone designing against the signal to realize that a distinction exists which needs to be worked with. But to casually dismiss the existing widespread ignorance of the fact that there is even a distinction between a standard time (e.g., what is broadcast on WWVB) and unsegmented time (what is desired for any system which computes intervals between timestamps) as an issue of engineering incompetence is a gross oversimplification, IMO. --Ken Pizzini
Re: pedagogically barren?
Markus Kuhn wrote: (stuff deleted) While the international inch is indeed linked to the meter by a reasonably round factor, and even shows up indirectly in a number of ISO standards (e.g., inch-based threads and pipes), this can clearly not be said for the US pound and the US gallon and units derived from these, which are still required by US federal law to be present on consumer packages. As long as it remains legal and even required in the US to price goods per gallon or pound (units completely unrelated to the inch!), (rest deleted) According to the NIST website, a gallon is defined as exactly 231 cubic inches. I would say that was a long way from being completely unrelated to the inch. While the pound is unrelated to the inch, it is defined as exactly 0.45359237 kilograms. Neither is a nice round number, but there is a definite relationship. William Thompson
Re: pedagogically barren?
Title: RE: [LEAPSECS] pedagogically barren? It's also true that changing to SI units for weight and volume is a lot more technically tractable than for length. Public opposition would still be a big barrier, though. /glen -Original Message- From: William Thompson [mailto:[EMAIL PROTECTED]] Sent: June 4, 2003 10:35 AM To: [EMAIL PROTECTED] Subject: Re: [LEAPSECS] pedagogically barren? Markus Kuhn wrote: (stuff deleted) While the international inch is indeed linked to the meter by a reasonably round factor, and even shows up indirectly in a number of ISO standards (e.g., inch-based threads and pipes), this can clearly not be said for the US pound and the US gallon and units derived from these, which are still required by US federal law to be present on consumer packages. As long as it remains legal and even required in the US to price goods per gallon or pound (units completely unrelated to the inch!), (rest deleted) According to the NIST website, a gallon is defined as exactly 231 cubic inches. I would say that was a long way from being completely unrelated to the inch. While the pound is unrelated to the inch, it is defined as exactly 0.45359237 kilograms. Neither is a nice round number, but there is a definite relationship. William Thompson This message may contain privileged and/or confidential information. If you have received this e-mail in error or are not the intended recipient, you may not use, copy, disseminate or distribute it; do not open any attachments, delete it immediately from your system and notify the sender promptly by e-mail that you have done so. Thank you.
