Re[2]: Use of femto scaling in IBIS models

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Andy,

This is exactly what we were debating in those conversations I was
referring to. Unfortunately, I don't remember for sure what the
decision was, but it seems to me that we said that it was the parser
that was valid. Could someone with sharper memory comment on this?

Regarding the prefixes, I would vote for making all of them valid.
Here is the table from the Electronics Engineer's Handbook by Donald
Christiansen, 4th edition, 1996, page 8.20. (I am not showing the
ones they do not recommend to be used). This is from ANSI/IEEE
Standard 268-1992 according to the footnote.

Factor Prefix Symbol

10+24 yotta Y
10+21 zetta Z
10+18 exa E
10+15 peta P
10+12 tera T
10+9 giga G
10+6 mega M
10+3 kilo k
10-3 milli m
10-6 micro u (using the Greek symbol mu)
10-9 nano n
10-12 pico p
10-15 femto f
10-18 atto a
10-21 zepto z
10-24 yocto y

Unrelated to IBIS matters in general, I also want to mention here (to
let my frustration out) that using the proper cases for units and
prefixes are important. I see many articles, books in print
(including some of the other chapters of the above mentioned handbook)
and software where the authors are negligent to follow the rules
of proper letter casing leading to confusion and ridiculous or
physically impossible units. Lots of examples could be brought up,
but some of the most frequent ones I see are:

correct unit incorrect spelling and its meaning
  and its
abbreviation

second, s "S" conductance, siemens
nanosecond, ns "nS" conductance, nanosiemens
kilo, k "K" temperature, kelvin
kilowatt, kW "KW" (?) kelvinwatt
milli, m "M" prefix, mega
Mega, M "m" prefix, milli
megahertz, MHz "mHz" or Mhz" millihertz or mega-hecto-zepto (?)
megabit, Mb "mB" or "mb" etc. millibyte or millibit etc.
megabyte MB "Mb" or "mB" etc. megabit or millibyte etc.
decibel dB "db" decibit

And so on. I wish engineers would take more pride in precision when
it comes to spelling in writing.

Arpad
=====================================================================

I don't question what may have have been previously discussed ... but
in my mind the only correct answer is that the spec ALWAYS takes
precedence, no matter what you're talking about. If the spec and the
parser disagree, you fix the parser.

If you want the parser to have precedence, then make IT the standard
with its source code freely available to the world, and make a note in
the spec that it is only an example and to refer to the parser.

I brought this issue up some two years ago with one or more of you.
Will "a" come to mean "alto" (1e-18) some time in the future? (It
already does on at least one simulator.) You need to get this nailed
down firmly. Otherwise you don't have a spec.

Regards,
Andy

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Subject: Re: Use of femto scaling in IBIS models
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To: arpad_muranyi@ccm.fm.intel.com
From: Andy Ingraham <ingraham@wrksys.ENET.dec.com>
Date: Wed, 27 Nov 96 08:52:14 EST
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