Re: [Phys-l] SI unit for time

["John Clement" <clement@hal-pc.org>]

Of course the physics police or the SI police will not get you if you use an
old fashioned abbreviation.

But there is a more serious breach of SI standards.  This is the use of the
k, M,... prefixes in the computer world.  Kilo or k stand for 1000, but the
computer world (not necessarily consistently) uses it to mean 1024 because
that makes it a simple binary number.  There is an IEEE standard to address
this where kibi (as I recall) would mean 1024.  Actually this problem might
eventually be solved, but not by the USA.  We can't seem to agree on any
standards.  If the Europeans insisted that computer systems adhere to SI
standards in labeling, this would be changed.

The real problem comes in when you look at things like file sizes.  Did they
use M according to SI, or according to computer usage.  It makes mental
arithmetic to convert Kbytes to Mbytes... essentially impossible.  One can
estimate, but that may not be good enough when you are concerned about
space.  Then of course they follow SI when quoting speeds.

I consider this to be a serious problem with respect to standards.  The
manufacturers could start advertising their hard drives according to SI
which would make the numbers slightly bigger.  I suspect that if one did it
all would follow, because of competition.  If MS followed SI when it quoted
sizes, I suspect the rest of the world would quickly follow.

John M. Clement
Houston, TX


> On 09/06/2008 11:19 PM, Julie Quah wrote:
> > i notice that the unit for time is still very much written as sec
> instead of
> > s, even in reputed Physics website. Anyone can enlighted?
>
> The canonical abbreviation is of course "s".
>
>  According to
>     http://physics.nist.gov/Pubs/SP330/sp330.pdf
>  "It is not permissible to use abbreviations for unit symbols or
>   unit names, such as sec ...."
>
>
> As the next step, if we are seeking enlightenment, the remaining
> question is "why"?  Why should we worry about this at all?  I
> don't like to tell students "do this because I said so" or
> "because BIPM said so".
>
>   The devil's advocate would point out that NIST and/or BIPM are
>   not going to arrest you for "impermissible" abbreviations.  As
>   for the "sec" abbreviation in particular, it has been in use
>   for thousands of years, and is "still very much" in use.
>
>   "Sec" is not even illogical:
>    *) It agrees with "min", which is the canonical abbreviation
>     for minute.
>    *) It has the advantage of being distinct from the "s" that
>     marks a plural in English (and some other languages).
>    *) Sometimes abbreviations become words in their own right.
>     The expression "Wait a sec" may be informal, but it is
>     perfectly grammatical.
>
> Switching now to the other side of the argument:
>
> The usual reason for preferring the canonical abbreviations is
> that the non-canonical ones are sometimes a burden on readers
> who don't speak your language fluently (or at all).  Hence the
> editors at international journals such as Phys. Rev. are going
> to insist on "s".  They have to draw the line somewhere.
>
> As for web sites in particular, realize that the WWW really is
> the World Wide Web.  My web site logs report lots of hits from
> really out-of-the-way places.
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