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Archive for December, 2013

The Death of Antigravity, Holiday Serial 2013, Part I

Monday, December 30th, 2013

Last Year’s Holiday Serial
Better late than never. I had a nice little holiday serial planned for this year that was going to detail the actual science done by the physicists peripherally mentioned in Nick Cook’s, “The Hunt for Zero Point“.  For those not familiar with it, Cook’s book is a rollicking good read in the fringe physics field that contains equal parts historical research, investigative reporting, and (very) speculative history.  I’d intended the serial to focus on the valuable and interesting physics that had been done as a result of the drive to ‘discover anti-gravity’ that Nick Cook describes as having taken place in the mid-1950s under the auspices of companies like the Glenn L. Martin Aircraft company and Bell Aircraft.  As any serious physicist will tell you, no serious physicist has ever worked on anti-gravity.  For that matter, no serious physicist feels really comfortable even saying the A word.  Consequently, the papers I intended to report on had nothing to do with anti-gravity except that the anti-gravity zeal of a few corporate and military leaders had funded them.  I didn’t figure I had much to add to Cook’s reported history either, still though, I thought the actual physics would be a nice point of interest.

After my last final of the semester, I plopped my copy of The Hunt for Zero Point into my bag, and hopped onto megabus headed for Dallas and the 27th Texas Symposium on Relativistic Astrophysics.  The symposium is only held every few years, so as it turned out, this year was the 50th anniversary of the original event which was held at the Southwest Institute for Advanced Studies, now known as the University of Texas at Dallas in 1963. Looking through the program it occurred to me that a lot of the people whose papers I intended to comment on in the holiday serial were actually going to be at the 50th anniversary symposium.  There was Rindler whose 1960 paper, “Hyperbolic Motion in Curved Space Time”[1], calculated how far a rocket could travel across the galaxy if it were able to accelerate constantly at 1 G.  Cecile DeWitt-Morette who figured prominently in part V of last year’s serial would be there.  Finally, Louis Witten who worked for the Research Institute for Advanced Studies which features prominently in “The Hunt for Zero Point” was on the program as well! I was looking forward to getting to hear their presentations, and hoped to possibly get to discuss some of their papers with them.

A roundtable discussion had been scheduled for the second day of the meeting when Rinder, DeWitt-Morette, Witten and several other scientists would reflect on their experiences in the field of relativistic astrophysics since the first Symposium in 1963.  I trundled onto the bus in downtown Dallas headed to the UT Dallas campus where the roundtable was to be held. As the bus navigated Dallas traffic in a shockingly efficient fashion, I enjoyed discussing a new observatory that was being constructed in the hill country west of Austin with my astronomer seatmate.  The auditorium for the roundtable was almost completely full and abuzz with conversations ranging from the application of the Casimir effect to biophysics, to what various audience members surmised the topic of the roundtable would be.

Some of the participants in the Texas Symposium Roundtable, starting from the left Charles Misner, Louis Witten, Cecile DeWitt-Morette, Roy Kerr, Joshua Goldberg, and James Anderson

As all the participants were seated, the moderator announced that the format would entail each of the participants, in alphabetical order, taking two minutes to reflect on what they found interesting in the 50 years since the original symposium. The moderator would then ask questions of the participants for the remaining portion of the scheduled one hour and forty-five minute roundtable.  The format was clearly more of a guideline than a rule, because after almost two hours of fascinating reminiscences from Anderson, DeWitt-Morette, Goldberg, Kerr, Misner, Penrose, and Rindler, Louis Witten took the microphone.  That’s when it happened.  Dr. Witten said that rather than discuss the birth of modern relativistic astrophysics that had taken place at the 1963 symposium, he would like to speak about a death, the death of anti-gravity!

References

1.  http://dx.doi.org/10.1103%2FPhysRev.119.2082
Rindler W. (1960). Hyperbolic Motion in Curved Space Time, Physical Review, 119 (6) 2082-2089. DOI: 

 

The Verification Walk and Talk

Wednesday, December 18th, 2013

I may be biased coming from a metric driven verification background, but 2013 seems to have been the year of the reusable metric driven verification environment.  We saw Jasper and Duolog team up to produce not only a re-usable specification, but associated assertions that could travel with it, and the IP from project to project. ARM is shipping these verification environments along with its IP blocks.  Apache touted the benefits of metric driven power verification.  The big three, Cadence, Synopsys, and Mentor, are all headed down variously similar metric driven verification process paths.  Gary Smith called for more reusable system verification that spanned the entire gamut between block level IP and user level apps.  Even physical design is moving to automated, metric driven verification as companies like Sage advance the technique.  Will we soon see packaging and board design tools from companies like Dassault be included in a metric driven flow?

With all the advances in tools, there’s still one personal aspect of the verification project to keep in mind, the true point of origin of all these tracked metrics: communications.  While metrics can and should be codified and tracked by automated tools, they are most effective when they are codified correctly based on a shared understanding of what a design is intended to do and how it is likely to be used.  This knowledge is contained in the minds of various members of the product design and production team.  Here are a few guidelines about what each part of the team might be able to contribute in the metric definition process.  They are by no means complete and additions based on your experience would be greatly appreciated.

Fellow Verification Team Members
Your fellow verification team members may have previously worked with the block you are tasked  to verify and have a historical knowledge of its ins and outs.  In addition to that, your blocks may be adjacent, or share common resources.  Hopefully, you’re both in good contact with your design engineers, (see the next section).  You should also be in good contact with each other.  Often hammering out metric details about inter-block communications identifies bugs without a single testcase being run.

Design Engineers
If you don’t know who your block’s design engineer is, you should find out.  This may not be as simple a task as it seems.  In some boutique semiconductor companies, they may only be a few cubes away.  In large international firms, they might be on the other side of the globe.  In either event, it’s worth the effort to get to know them.  These folks are putting their understanding of the specification into physical realization.  You’ll want to make sure that you’re checking the design vs. what they think it should do as well as what the specification says it should do.  Here as in the section above, good communications can lead to bugs being found without executing any testcases.
Firmware Engineers
These people will use the device utilizing its exposed interfaces.  They can tell you how they’ll use the device.  This usage model defines known sequences of transactions that the device will  be expected to perform.  They can also tell you which portions of the device’s functionality have the highest priority.
Architects
Architects specify how the system is to be stitched together and share resources.  They can help identify stress tests to run the system through its paces.  They can also be invaluable in helping you get a big picture of the device you’re testing from the top down.
Marketing
Despite all the two-drink minimum jokes about marketing, they often have the deepest knowledge of how the device’s customers want to use it.   This knowledge can help in defining must-be-run test sequences and in prioritizing verification tasks.
Production Test
Even though its well after the fact, verification sequences run in production test sometimes expose use case relations between blocks you didn’t know existed.  Test engineers are privy to this sort of thing.  They should especially be engaged for verification planning of derivative products, and let’s face it, what’s not a derivative product these days?

Hopefully I’ve made a good case for communicating early and often with your project team.  In case I haven’t, you might want to think about one extra aspect: the fringe benefits.  Talking to these folks makes you a known quantity around the company and with the fluidity of our industry, over a few years can gain you exposure across multiple companies.  As you get ready to move into other areas of project execution, or to move into positions with more responsibility, being known as a communicator that makes a positive impact can only help.

 

Is the Golden Age of Builders Returning?

Sunday, December 15th, 2013

The above picture is taken from “Practical Radio” by Henry Smith Williams.  This authoritative tome, published in 1922 details how one might go about getting into the ‘radio game’.  The entire first chapter is rife with passages like the following:

Thousands of them [youngsters] – tens of thousands – who a year or two ago would have lingered after school to play marbles or to bat a ball about a vacant lot… now hurry home and rush up to the attic where their radio outfit is installed in order to do a little tinkering before suppertime….

Lest, looking at the picture above, you think only boys were interested in radio, fear not, girls were in on the game as well:

The book goes on to describe a scene witnessed by one of the authors associates wherein three students were peppering a salesman at a local radio store with questions well out of his depth.  They were able to ask such questions because they had all constructed their own radios.  With the advent of the Arduino and other project computers, I’ve wondered if we might be on the verge of a new era of very well-informed builder-consumers, people who had built their own special purpose digital and/or analog systems from the ground up.  However, as far as the Arduino and company have brought us, I still had doubts.

Long-time readers might remember that I bemoaned all the extra circuitry on a typical Arduino board and patiently waited until the naked Arduino was available.  I loved being able to handle the project’s individual components and have a solid feel for what each of them did.  I’ll let you in on a secret though.  Even with the naked Arduino shown below, I was still a little irked.  Why?  The USB interface on the left-hand edge of the plug board was the culprit.

To paraphrase one of our politicians, I didn’t build that!  The microcontroller, and the crystal were as bare as could be, but that USB interface was custom designed and sourced by someone else.  To be fair, I didn’t have the time to study data sheets, select a USB to SPI interface chip, design a printed circuit board and layout the surface mount components.  So, in a very real way, the little interface card was certainly worth it.  On the other hand though, there was no getting around it, there was a portion of my circuit that I had to depend on someone else for.

An item from this week’s low-power news, however, gives me hope that we’re one step closer to being able to source our own devices if we’re so inclined.  For a mere $20 U.S. any project designer in the world can try out Silicon Lab’s new USB to SPI interface chip.  Perhaps gone forever are the days of mooning over the latest and greatest device, finding out that the manufacturer has made a handy evaluation board available and then having your dreams dashed when it turns out the price of the board runs upwards of $500.  For the mere pittance that Silicon Labs is charging, the industrious builder gets the evaluation board shown here, a mini USB extension cable, the CP2130 Quick start guide, and a CP21xx kit installation DVD!  I’ve ordered mine.  I’ll keep you posted!