From: Jonathan Dowling (email@example.com)
Date: Wed Jan 19 2000 - 10:26:47 PST
I'll tell you what.....Let's make a deal !!
In the spirit of Andy Rooney's offer of $1,000,000.00 to anyone who can identify Nicole's
In America, we vote with dollars. Instead of arguing, lets put it to such a vote.
Given that Intel is the bellweather of the industry and given that the membership of the
SI-LIST is dominated by Intel employees (as Ray can attest), the tool adoption trend
seen there should more or less be reflected in the majority of the industry.
I'm willing to concede the point when Intel can definitively report that it has less than
100 IBIS compatible simulator licenses. This means all XTK, ICX, SpecctraQuest
licenses and other IBIS-like simulators. This includes those of you who use linear excitation for
MDS/ADS and Speed97. Consider yourselves behaviorists. Those who use the behavioral
modeling facility in Hspice should also be included.
My best guess is that they have:
If Intel does have more than 100 IBIS compatible simulator licenses, how does this square with
"the death of IBIS" scenario?
Argueably, the worst problem with behavioral simulators is that they do not (or poorly) predict
switching noise. The trend to convert to differential signaling eliminates this problem by
suppressing SSO by 20x. This should enable a renaissance in behavioral modeling and
should increase its adoption rather than serve as a restriction.
Interconnect researchers using Spice may want to find out who is bankrolling their research
these days. It may not say so on your paycheck, but while you fight convergence problems, someone
using a behavioral simulator is paying your bills through the design of real, timely products
that make real money.
--- Chris Cheng <firstname.lastname@example.org> wrote:
> hmmm.... interesting. i wonder who design gtl buses first ?
> ahh.... its got to be mr. gunning cause its called gunning tranceiver
> ohhh.... he designed it first with a company call what ?
> so.... please check who published the first system/bus design paper
> in the industry on gtl. i give u a hint, the first author's name starts
> with a c. and i assure u he only used spice to design the first gtl
> system with 10 slot loading at 66MHz without a dead cycle in the
> days of 80486.
> for the record, i defined the corp. cad signal intrigity methodology
> in sun more than 10 years ago and for sure behavoral model was in
> it but over time performance requirement and accuarcy concern has
> shift everything to spice. yes, i am still using behavoral model
> when i am designing pci or jtag but it stops there.
> actually intel has boat loads of spice license too (its free since
> its in house tool). so i don't understand your comment on 100's of
> behavoral simulators.
> -----Original Message-----
> From: email@example.com
> [mailto:firstname.lastname@example.org]On Behalf Of Jonathan Dowling
> Sent: Tuesday, January 18, 2000 5:57 PM
> To: email@example.com
> Subject: Re: [SI-LIST] : receiver jitter
> Newbies: Time for a history lesson...
> I would be willing to bet Chris' sentiments today were issued
> verbatim by critics of behavioral modeling at the folks who
> developed behavioral simulators in the 1980's (or before).
> Proponents of SPICE have long criticized IBIS-like simulators,
> even when signal quality not an issue (only timing).
> If we go back in time we would hear:
> "We are going to be running at 4MHz this year. You can't correctly
> predict timing with a behavioral model. This is 5V logic. You will
> have to use SPICE. Specifically, you can't model the receiver well
> The true test is time-to-market. Almost without exception, all
> the companies that excel at time-to-market in the digital world
> have boatloads of behavioral simulator licenses. Intel is the
> best example of this fact because they make the most money.
> Their behavioral simulator licenses number in the 100's. If you
> claim your company excels at time-to-market without behavioral
> simulation, I claim your company is not as successful as Intel.
> Rambus's SPICE bigotry certainly contributed to their poor
> time-to-market showing last year. Maybe they don't have a single
> behavioral simulator in-house. They were generous enough to make
> an IBIS model, but it was pooh-poohed by the 'experts' who claimed
> (on this reflector list) that only the SPICE model would do.
> Simulation with the simple IBIS model is enough to show timing
> marginality at 800MT/s. (By the way, it looks great at 600MT/s
> if you're lucky enough to avoid the resonances.)
> Jonathan Dowling
> --- Chris Cheng <firstname.lastname@example.org> wrote:
> > as core and signal swing getting smaller and smaller, this
> > problem is getting worst. compound this with source sync
> > buses where the strobes and data can behave differently
> > (true differential vs. pseudo differential), i believe
> > predicting the response of the receiver under different
> > waveforms input will be as important as simulating
> > the propagation of signal in the interconnect
> > environment. this will be the final nail in the coffin for
> > behavioral models like ibis which is totally incapable of
> > handling such analysis. i have seen pitiful attempts to
> > qualitatively describe it in ring back or edge rate
> > extrapolation but without the ability to simulate the
> > receiver behavior, those specs are just fancy words with
> > no meaningful insight into the response of the true
> > receiver.
> > can i spell SPICE again.
> > chris
> Do You Yahoo!?
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