An Engineer's Literary Notebook

Exploring the real and surreal connections between poetry and engineering

Memory of The Future

Posted by xbanguyen on November 8, 2009

If you have a choice between experiencing a perfect moment and having an everlasting memory of such moment but never actually experiencing it, which one would you choose? There was a time when I would choose the former, like Hans Christian Andersen’s little match girl, for a brief moment of warmth before the eternal oblivion. Now it is the latter, perhaps because of a desire to relive certain moments that become real again upon recollection. Moreover, the selective recollection can be done at will.

In my line of work, memory is actually tangible, semiconductor memory, that is.  From the early days of Texas Instruments’s series 51 that offered a few hundred bits of memory to the multi gigabit devices of today, the amount of memory that can be stored in a small space is amazing, if you would just let yourself to be amazed. To put things in perspectives, the size of all six volumes of Gibbon’s History of the Decline and Fall of the Roman Empire is 200 mega bytes, a mere fraction of what can be stored in a 16 giga bytes NAND flash device whose die size is 20 mm X 13 mm.  Conventional non volatile memory is built with transistors.  In the not too-far-off future, the fourth fundamental element, the memristor, can be used in building persistent memory devices with higher density and consume less power.  Unlike the resistor, the memristor retains its last value when there is no current flow through it.  It too has memory.

Of course it is not always good to be able to retain so much memory.  Not because of nothing that Dali painted the persistence of memory so eloquently and eerily.  Sometimes it is a blessing to forget.  To use the words of Emily Dickinson:

To flee from memory
Had we the Wings
Many would fly
Inured to slower things
Birds with surprise
Would scan the cowering Van
Of men escaping
From the mind of man

Emily Dickinson

It takes a copious amount of self-delusion to filter out the unwanted memory and to add beauty to the wanted. Is it total honesty? No, but the dappled shade added later to block out the falling branch provides a needed contrast to make the leafy lane appear a lot greener, a lot more pleasant to revisit this November evening.  What about “To thine own self be true”?  Such hard choices.


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The Integrals In Things Past

Posted by xbanguyen on October 24, 2009

The integral sign \intreminds me of the salt water taffy machines in the  sweet shops of the Oregon coastal towns we  visited during the summers of my girlhood. I remember pressing my nose against the glass partition to watch  the machine pulled the strands of candy in a mesmerizing pattern over and over,  stretching them into almost living things – supple and touchable.  As I look back, those summers appear pleasantly long and unfocused like the desultory walks along the beaches, trading taffy flavors and seashells with my sisters.   The fact that a mathematical sign can invoke such nostalgia made me reach out for an old textbook tonight.  Full of equations yellowed out with highlighters by my former self, it patiently repeats to  me that the Volterra series has the ability to capture the effects of memory.  Differing from the Taylor series that approximates the response of a non-linear system such that the output is solely dependent on the inputs at a particular time, the Volterra series calculates the output using the inputs at all other times.  Specifically, it is a series of infinite sums of multidimensional convolutional integrals and can be used to calculate the intermodulation effect of audio signals.

The integral of rational functions can also be used to calculate the drag force effect on the free fall of a sky diver.  But this fact was of no use to John Gillespie Magee whose parachute failed to open one summer day in 1941.  But how he had lived!

High Flight
by John Gillespie Magee, Jr.
Oh, I have slipped the surly bonds of earth,
And danced the skies on laughter-silvered wings;
Sunward I’ve climbed, and joined the tumbling mirth
Of sun-split clouds…and done a hundred things
You have not dreamed of…wheeled and soared and swung
High in the sunlit silence. Hov’ring there,
I’ve chased the shouting wind along, and flung
My eager craft through footless halls of air.
Up, up, the long, delirious burning blue
I’ve topped the windswept heights with easy grace
Where never lark, nor even eagle flew.
And while with silent, lifting mind I’ve trod
The high untrespassed sanctity of space…
…put out my hand, and touched the face of God.

High Flight

by John Gillespie Magee, Jr.

Oh, I have slipped the surly bonds of earth,

And danced the skies on laughter-silvered wings;

Sunward I’ve climbed, and joined the tumbling mirth

Of sun-split clouds…and done a hundred things

You have not dreamed of…wheeled and soared and swung

High in the sunlit silence. Hov’ring there,

I’ve chased the shouting wind along, and flung

My eager craft through footless halls of air.

Up, up, the long, delirious burning blue

I’ve topped the windswept heights with easy grace

Where never lark, nor even eagle flew.

And while with silent, lifting mind I’ve trod

The high untrespassed sanctity of space…

…put out my hand, and touched the face of God.

John was nineteen when he died.  It was a farmer who saw him falling from the plane. The same force must have acted upon Icarus of the Grecian myth, another boy who fell out of the sky.  W. H. Auden offers some commentaries on how  these tragedies were perceived and interpreted by arts.

Musee des Beaux Arts

About suffering they were never wrong,

The Old Masters; how well, they understood

Its human position; how it takes place

While someone else is eating or opening a window or just walking dully along;

How, when the aged are reverently, passionately waiting

For the miraculous birth, there always must be

Children who did not specially want it to happen, skating

On a pond at the edge of the wood:

They never forgot

That even the dreadful martyrdom must run its course

Anyhow in a corner, some untidy spot

Where the dogs go on with their doggy life and the torturer’s horse

Scratches its innocent behind on a tree.

In Breughel’s Icarus, for instance: how everything turns away

Quite leisurely from the disaster; the ploughman may

Have heard the splash, the forsaken cry,

But for him it was not an important failure; the sun shone

As it had to on the white legs disappearing into the green

Water; and the expensive delicate ship that must have seen

Something amazing, a boy falling out of the sky,

had somewhere to get to and sailed calmly on.

W. H. Auden

It is cold comfort to be offered the permanence in the nature of gravity.  Looking at the poems from another angle,  I see that there are worse things than to be desensitized by arts. After all, having a susceptible heart  I need  all the help I can get to be inoculated against the rampant pain radiating from too many tragedies, both real and mythical.

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An Attraction Unexplained

Posted by xbanguyen on October 4, 2009

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Of Negative Capacitance And Nightingale

Posted by xbanguyen on September 20, 2009

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Deja Vu Deconstructed

Posted by xbanguyen on September 13, 2009

Bavarian Gentians

Not every man has gentians in his house
in Soft September, at slow, Sad Michaelmas.

Bavarian gentians, big and dark, only dark
darkening the daytime torchlike with the smoking blueness of Pluto’s
      gloom,
ribbed and torchlike, with their blaze of darkness spread blue
down flattening into points, flattened under the sweep of white day
torch-flower of the blue-smoking darkness, Pluto’s dark-blue daze,
black lamps from the halls of Dis, burning dark blue,
giving off darkness, blue darkness, as Demeter’s pale lamps give off
      light,
lead me then, lead me the way …

Memory is amorphous.  I still remember the first times I read that D. H. Lawrence’s poem.  The first time, you will want to correct me.  But I still can’t be sure.  All I remember  is that when I opened that volume of poetry, a graduation present, the morning after the commencement and read that poem,  I know that I had lived that moment before,  had followed those very words while the sunlight cast a peculiar  sheen on my graduation gown hanging on the hook next to the bookcase and the room was heavy with the scent of L’air Du Temps — another gift from my mother that I promptly broke in the excitement of the night before.   But it was not possible.  How could it be?  Nevertheless  the double sensation remains firmly in my memory years later.

But perhaps I had experienced that moment just a moment before.  If human memory is like certain type of  semiconductor memory that needs a clock to register, perhaps  deja vu can be explained as being a glitch on the clock edge.  At the first clock edge, my consciousness registered the entire tableau — the poem, the sunlight,  the scent and all.  The glitch followed immediately and I relived the same experience.  Even though very small, actual time has elapsed between the two edges,  making the two experiences similar and yet separate.  The question remains to be answered is the cause of the glitch and whether it can be induced.  Regardless of how or when I first read the poem,  the word Michaelmas was full of melancholy even before I looked up its meanings.  It is September and I am trying to be reconciled with the changing of seasons.

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The Synchronous Villanelle

Posted by xbanguyen on August 23, 2009

Patterns have many uses in digital design,  one of which is testing semiconductor memories.    Memory tests are different from  logic tests because memory test patterns can be completely  algorithmically generated, each pattern used to target a specific failure mode.  Some of the common patterns are galloping ones/zeroes, checker boards, sliding diagonal, walking zeroes and walking ones in which  a binary one walks across a field of zeroes to catch opened cell, short and address uniqueness.   A field of zeroes brings to mind the Tuscan hills probably because it is verbally related to  a field of daisies.  Daisies are similar to sunflowers — both can probably be used to play the game “he loves me, he loves me not”, and the Tuscan hills were extravagantly  decorated with fields of sunflowers during our trip to Italy some years ago, bringing with it the scent of rosemary, the simmering walls of Sienna seen from a hilltop,  the dappled shade of the olive orchard and the dusky grapes that conjured up Keats’s beaded bubbles all jumbled together like in a reverie. But then and there I actually had to remind myself that I was in Tuscany, sitting on a terrace by a rickety table complete with a plate of bread and olive oil while the afternoon sun turned the city below into a mirage.  Afterward the  interior of the farmhouse appeared cool and dark like the inside of a church made earthy with the fragrance from the pot of pappa al pomodoro bubbling on the stove.

That was then.  What I really planned to write about tonight was how the patterns inherent in the  rhymes and the formal meters found in certain types of poems make them more compelling. I am thinking of the sestina and especially the villanelle.  The villanelle  originates from the Italian word villa (that may also explain my prior preoccupation).   In case you are not yet familiar with this form of poems, a villanelle consists of nineteen lines, five tercets and one quatrain, carrying a specific rhyming pattern with the first and third line of the first tercet repeated in alternating order in the remaining stanzas and appear together in the quatrain at the end. Consider this most beloved villanelle — by now you already  know that I do wear my heart on my fingertips.

Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

Though wise men at their end know dark is right,
Because their words had forked no lightning they
Do not go gentle into that good night.

Good men, the last wave by, crying how bright
Their frail deeds might have danced in a green bay,
Rage, rage against the dying of the light.

Wild men who caught and sang the sun in flight,
And learn, too late, they grieved it on its way,
Do not go gentle into that good night.

Grave men, near death, who see with blinding sight
Blind eyes could blaze like meteors and be gay,
Rage, rage against the dying of the light.

And you, my father, there on that sad height,
Curse, bless, me now with your fierce tears, I pray.
Do not go gentle into that good night.
Rage, rage against the dying of the light.

Dylan Thomas

Do you feel the pull of the repeating patterns?  I wonder if the poet found comfort in using these patterns to keep his grief at bay.  As  for me,  I feel the indelible imprint of time in the cadence of the poem that synchronously lures me into accepting the inevitable … as if I have a choice, the fierce insistence of the refrain notwithstanding.

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The Eyes Of The Transceivers

Posted by xbanguyen on August 16, 2009

At my first job as an engineer,  next to the block diagram of the FPS564 array processor, I adorned the wall of my first cubicle which the following lines:

Each morning a thousand roses brings,  you say.

Yes, but where leave the rose of yesterday?

Even though their proximity was somewhat incongruous, the two displays coexisted more or less peacefully. Because over-analyzing is an occupational hazard, when I looked up from the monitor to refocus my eyes at at different focal distances as they said I should, I often wondered why I was attracted by those two lines from the Rubaiyat.  The words they contained were ordinary. Perhaps it was the rhythm? Or perhaps it was the sense of yearning, of empathy, of regrets because nothing, least of all a flower, lasted?  Sometimes I cringed at how sentimental it all sounded.  Other times I embraced the pleasurable melancholy (why it is pleasurable is the subject of another post, I think) even as I attended design reviews.  Unlikely as it might appear, the duality of those thoughts provided me with such clarity of vision into the technical concepts being presented, perhaps because the vision was enhanced by the pleasure provided by the connection between the limbic system and the prefrontal cortex as the poem took on a life of its own.

This reflection occurred to me tonight when I reviewed the techniques to widen the eyes of high-speed digital transceivers. To do so, transmitted signals are pre-emphasized to counter the attenuation incurred as the signals traverse toward the receivers.   The wider the eyes the better as the error rates would be reduced.   Would that it were possible to widen my own eyes to retrieve the same clarity possessed by that engineer, she of the faded flower taped on a cubicle wall, many years ago.

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“The Psychoanalysis of Fire”

Posted by xbanguyen on August 12, 2009

A  low power design technique known as clock gating is simple, almost  zen-like: if you don’t need a particular function in a circuit then keep it still by turning off its clock.   Static power used to be  insignificant compared to dynamic power. However, as we advance deeper and deeper into sub-micron territory,  sub-threshold leakage causes the amount of static power dissipation to increase exponentially.   While I think it is necessary to find ways to reduce power consumption for obvious reasons, I wonder if it can make an engineer harbor a longing for the other extreme.  I am thinking of thermal attraction in the literal sense, of the pyromantic images evoked by that primal force, fire.  This brings  Gaston Bachelard’s  “The Psychoanalysis Of Fire” to mind.  It takes an astonishing book to psychoanalyze such force:

“If all that changes slowly may be explained by life, all that changes quickly is explained by fire. Fire is the ultra-living element. It is intimate and it is universal. It lives in our heart. It lives in the sky. It rises from the depths of the substance and offers itself with the warmth of love. Or it can go back down into the substance and hide there, latent and pent-up, like hate and vengeance. Among all phenomena, it is really the only one to which there can be so definitely attributed the opposing values of good and evil. It shines in Paradise. It burns in Hell. It is gentleness and torture. It is cookery and it is apocalypse.”

It is also presumptuous of me to feel a kinship for the writer of the above passage, a professor of philosophy, chemistry and physics at the same time, but it does not stop me from doing so.  And I fell head over heels for his other books.  How could I not with titles like  On Imagination And Reverie, The Poetics of Space? It was the last book that led me to this  Rainer Maria Rilke’s poem.

What skies are mirrored

within the inner lake

of these open roses?

They can barely stand by themselves

many swollen to the point of bursting

overflow with inner space

into days which enclose

an ever vaster fullness

until the entire summer becomes

a chamber within a dream.

To me the poem exudes a heady, almost voluptuous, opulence.  And have you noticed how often summer recurs in these few posts of mine?  Perhaps I too have been consumed by the warmth we enjoyed in the recent past.

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Of Contentment and Metastability

Posted by xbanguyen on August 5, 2009

There is probably an interesting lesson in etymology explaining the origin of the words contentment and contention.   Contentment is a state of mind that follows the ebullient feeling one gets after figuring out that signal contention due to the asymmetrical rise and fall times  of an inverter is the cause of a failed data transfer.   Such are the moments  that make engineering an appealing profession.  There is an underlying sense of optimism in our line of work because we believe that for every engineering problem there is at least one solution.  We’ll keep looking until it’s found.  And somewhere along the way, if we shift our perspectives just a little when letting our left brains rest, we’ll also find that certain technical words carry their own kind of charm.

Consider clock domain crossing.   The word domain and demesne share the same Latin root.  I like them both, but that is the subject of another post. The idea that we can create multiple domains of time holds a certain attraction (because it gives us an illusion of being in control, to have dominion, over time?)   Nevertheless we don’t take clock domain crossing lightly because just like any time we transcend a boundary, there are dangers. In this case it is metastability.  Technical cautions aside, there are such opposing forces in a single word, metastability, that give it a certain cachet.  The bipolar nature of digital signals is such that signals that fall within that forbidden window will oscillate, not at all a desirable state of being.  So just like the “watch out for the baobabs”  warning reiterated by the pilot who befriended the Little Prince in the Sahara, I would like to reiterate a similar warning to the young engineering students to watch out for unsynchronized signals when crossing clock domains.  And yes, just like it is easy to pull out the seedling baobabs from the tiny planet, it is easy to add a couple of flip flops to prevent the potential disaster.

Speaking of opposing forces, they can be found in this stanza of a favorite poem by Dylan Thomas, a fitting way to end this post.


The force that through the green fuse drives the flower
Drives my green age; that blasts the roots of trees
Is my destroyer.
And I am dumb to tell the crooked rose
My youth is bent by the same wintry fever.

The force that through the green fuse drives the flower
Drives my green age; that blasts the roots of trees
Is my destroyer.
And I am dumb to tell the crooked rose
My youth is bent by the same wintry fever.

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A Time To Measure

Posted by xbanguyen on August 4, 2009

Somehow the idea that we can measure a very small amount of time, a femtosecond for instance, really appeals to me. It does not matter that it is not I who can do the measuring. Paradoxically I also take pleasure in knowing that the electrons will go their own ways regardless whether or not they are used as the tools for such measurements. The idea that tiny particles are now going about their business in the void that is my body is compelling.  For me, time has often been a scarce commodity.  So it’s fitting to begin my first post this way. Rereading what I wrote pre-blog, my haphazard collection of essays and the overwrought poems  stuck in a directory somewhere on this hard-drive makes me think that I need to deal with time first and it won’t be the last time. So how do I deal with time? Why am I blogging now instead of sleeping? It’s past midnight here in my part of the world.

Let’s throw time into the soup made up of one part beauty and two parts faith (no, not that kind, perhaps later).    I’ve found that sometimes beauty shows up at unexpected places.  Take simulation waveforms, for example.  In my  work as an an engineer for  a company that makes medical devices, I often use waveforms to trouble shoot logic problems.  The waveforms are often green — I want to say chartreuse green because I like the word chartreuse, but it would not be accurate.  So they are green against the default black background.  Pages full of waveforms can weave themselves into striking patterns as I zoom in and out in search for clues.   There are always clues.  One has to believe in logic, with passion at times, that the causes that manifest themselves in a particular bug will be found even if it appears confounding.  At the same time one has to proceed with dispassion, methodically, to find the pesky thing.  And simulation waveforms are displayed in units of time, mostly nanoseconds.   How many nanoseconds has it been since Andrew Marvell wrote these lines?

But at my back I always hear

Time’s winged chariot hurrying near

Most of the time I forget about the amorous intention of the poet and only hear that relentless chariot  gaining on me.  But what would happen if it catches up with me?  What am I really afraid of?  That there will not be another summer as delightful as this one has been?  While I don’t disagree with Henry James that summer afternoon are the two most beautiful words in the English language, I think that summer morning are possibly better.  Just the potentials alone make it so.  The summer morning sky takes on such impossibly vivid blue that colors the coming day with a sheen of possibility.  Even the early summer morning air feels different, fresh with not only a hint of promises but also seductive with the certainty of promises fulfilled.  Get up really early tomorrow morning, stand in front of  the open window and breathe in deeply.  You’ll know what I mean.

Come to think of it, there is something melancholy about a summer afternoon, the charm of having a cream tea completed with cucumber sandwiches and scones notwithstanding because dusk approaches and with it comes darkness.    But what about the stars?  What about the scent of jasmine? What about the fireflies and other things of beauty that accompany twilight?  Perhaps I am missing the point while seeking an illusion of permanence.

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