[Tinyos Core WG] Unit of time in TOS2

[Vlado Handziski]

Who from you guys goes under the name  "Ingle" on wikipedia? This was added
by him yesterday to http://en.wikipedia.org/wiki/Binary_prefix

[[Embedded system|Embedded systems]], on the other hand, may perform timing
operations as binary fractions of one second. This stems from the prevalance
of microcontroller operating frequencies as even powers of two (such as 4
mebihertz) for deriving 2^-20 seconds and 32768 Hz [[Real-time
clock|real-time clocks]] for deriving 2^-15 seconds and 2^-10 seconds. In
this context, to avoid confusion with milliseconds and microseconds, some
systems are adopting the informal prefixes "milbi" for 2^-10 and "micbi" for
2^-20 to uniquely describe the milbisecond and micbisecond.

I guess now it is official :)

Vlado


On 10/19/06, Cory Sharp <cory at moteiv.com> wrote:
>
> I'll actually give Rob S most the credit :).  - Cory
>
> On 10/19/06, Joe Polastre <joe at polastre.com> wrote:
> >
> > Martin and Cory came up with the idea of applying the binary prefixes
> > to negative exponents at the Moteiv offices earlier this week.  Cory
> > also had a post about it to the 2.0 working group a few days ago.
> >
> > -Joe
> >
> > On 10/19/06, Martin Turon <mturon at xbow.com> wrote:
> > >
> > >
> > >
> > >
> > > I agree that TMilbi is the right naming.
> > >
> > >  Is Martin L. the first to define negative exponent binary
> > prefixes?  This
> > > is a cool idea.  It would be good to use an "official" name, or to
> > propose
> > > the names to NIST/SI or even just on wikipedia.
> > >
> > >  Martin
> > >
> > >
> > >  -----Original Message-----
> > >  From: tinyos-2.0wg-bounces at Mail.Millennium.Berkeley.EDU on
> > > behalf of Martin Leopold
> > >  Sent: Thu 10/19/2006 12:23 PM
> > >  To: tinyos-2.0wg at Mail.Millennium.Berkeley.EDU
> > >  Subject: [Tinyos Core WG] Unit of time in TOS2
> > >
> > >  Hi All.
> > >  While reading the Timer TEP (102) a question came up regarding the
> > use
> > >  units to denote the precision for the timers. The TEP is confusing on
> > >  the part on what TMilli means - is it 1/1024 s or is it 1/1000 s (as
> > the
> > >  name suggests). The TEP should be clear and I believe Cory has
> > already
> > >  fixed that, but I think the question is a little deeper - mixing 1000
> > >  and 1024 units could in the end lead to misunderstandings.
> > >
> > >  I'm not trying to say that the timer unit should be ms, but that it
> > >  would be elegant if the name reflected what you really get - there is
> > >  plenty of good reason for using 1/1024 s instead of ms. My feeling is
> >
> > >  that even if it's put in the FAQ, tutorials and documentation, at
> > some
> > >  point some poor bloke is going to come along and use the TMilli as ms
> > in
> > >  a calculation, which is wrong.
> > >
> > >  So what are the thoughts on this? Is it enough to be precise in the
> > >  documentation, or is a name change appropriate?
> > >
> > >  I ran into Cory and we talked about what the name should be (if it
> > were
> > >  to be changed). And resembling the KiB, MiB seems like a good idea,
> > but
> > >  unfortunately they don't define negative exponents. So in the spirit
> > of
> > >  the kibi/mebi units milli would become milbi and micro would be micbi
> > >  and the precision tag names TMilbi/TMicbi.
> > >   http://physics.nist.gov/cuu/Units/binary.html
> > >
> > >  --
> > >  Regards Martin Leopold.
> > >  Dept. of Computer Science, University of Copenhagen
> > >  http://www.diku.dk/~leopold <http://www.diku.dk/%7Eleopold>
> > >
> > >
> > >
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> > >
> > >
> > >
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