The autumn leaves are falling like rain. Although my neighbors are all barbarians and you, you are a thousand miles away, there are always two cups at my table.

T’ang Dynasty poem

Ten thousand flowers in spring, the moon in autumn, a cool breeze in summer, snow in winter. If your mind isn't clouded by unnecessary things, this is the best season of your life.

~ Wu-men ~

Sunday, July 03, 2005

On Technology

At seaBy Jack Ganssle, Embedded.comJun 29 2005 (15:31 PM)URL:

Dateline: 28 07N, 68 23W, 350 nautical miles south ofBermuda, 1000 miles east of Florida

In the 70s I bought a 40-year-old wooden sailboat fora pittance. Though at first little more that afloating assembly of wooden boards moored in nearproximity to each other, a couple of years ofpart-time work restored her to near-pristinecondition.

I replaced the 2,080 screws that held her hulltogether, the deck, the keel bolts, and far more.Eventually, flush with all of $1,500 and the optimismof youth, Arwen and I headed south from Maryland tosail around the world.

Though Arwen's purchase and refitting had all beenfinanced by my job as an embedded systems engineer,the boat had nary a single microprocessor on board. Inthose days stereos, such as they were, used analogtuners. The depth sounder was a piece of lead on amarked line, heaved frantically overboard only whenthe water looked thin.

Even the EPIRB--an emergency radio transmitter thatemitted a warble on aircraft
distressfrequencies--used but a bit of analog circuitry. Notenough, it turned out, to be effective when acontainer north of Cuba left me drifting in aliferaft. Low tech flares saved the day.

How things have changed. My current boat, built in thesame (1977) year Arwen and I left for points unknown,fairly bristles with antenna and electronic systems.As I write this in mid-ocean, a thousand miles east ofFlorida, bound for the island of Grand Turk, an 8051in Voyager's autopilot steers.

Only my wife and I are aboard so it's nearlyimpossible to keep a watch all the time, so the radarsweeps silently all night long, emitting a beepwhenever a target intrudes within a 10-mile guardzone. The beep is too quiet to alert these sleepingears, so I've tied the radar into a network. APIC-based box extracts the beep message and sounds aklaxon. The GPS passes position data back to the radarscreen; when a ship appears it takes but a moment toplace the cursor over the dot and get the vessel'sexact position.

The ham radio's DSP enhances weak signals. Our marineVHF radio scans multiple channels constantly. Adigital battery monitor displays the state of chargeof the twin 6-volt golf cart cells, and asimilarly-smart voltage regulator generates fourdifferent kinds of charging regimes to keep thebatteries topped off. The utterly-essential Dell MP3player (fondly christened a "DellPod") feeds 2,500sounds from its hard disk to a smart stereo.
Most astonishing of all is the GPS. It's a small unit, bulkhead-mounted,that constantly shows our position with an accuracy of meters. Oncenavigation was an arcane art, kept secret by ships' officers so crewscouldn't take the risk of mutiny. Now I turn the unit on at the start of thevoyage and do nothing more than watch our position update each second. WhatCaptain Cook would have given for such powerful magic!

Oddly, though, the charts are still crude, many ofthese remote islands based on surveys from the 19thcentury. It's ironic that the cheap little GPS is farmore accurate than the charts produced at greatgovernment expense.

On Arwen I navigated with a sextant, a slice ofantiquity that accurately measures angles. Given theangle between the sun or a star and the horizon, plusthe time, a bit of math produces a line of position.But there's quite a bit of skill required, and eventhe best navigators are happy with a mile or two oferror. Clouds thwart any sextant sight; over thecenturies hundreds of ships and thousands of liveshave been lost due to simple math errors and dank,dismal skies.

Today that same sextant lives over Voyager's charttable. I shot the sun and Jupiter yesterday, andreassured Marybeth that the GPS is still workingcorrectly. One wag suggested putting it behind a glasscase with a sign "break glass in case GPS fails." Butthe fact is one can now buy a dozen GPS devices forthe cost of one good sextant. The technology has trulyrendered celestial navigation obsolete.

Poor winds have had us motoring far too much.Voyager's three decade-old diesel is mercifullyprocessor-free, but I've been thinking about buildinga simple two wire network of
epoxy-coated CPUs andsensors to monitor its health.

In the 1,500 miles since we left Baltimore theautopilot chewed up a belt. One cabinet latch failed.Fish ate two lures. The engine is leaking just a bitof oil and might need an injector replacement. Theanchor light burned out, and one sail needs a bit ofattention. But every bit of electronics worksflawlessly.

I often rant about the state of the embedded art. Toomany systems are unreliable and bug-ridden. Yet evenon the anachronism of a sailboat, our lives areimproved and coddled by processor wizardry.

One report suggested that the average home has over200 micros today. Embedded systems are the glue thatholds the 21st century together. Frustratingly, fewnon-techies know what the word "embedded" even means,despite their utter reliance on an implanted pacemakeror smart coffee-maker.

It seems there's always an anti-technology backlash.People move back to the land. They reject the power ofscience; some yearn for Walden Pond. Me, I embrace thesort of life our smart electronics has created. Howabout you?

Jack G. Ganssle is a lecturer and consultant onembedded development issues. He conducts seminars onembedded systems and helps companies with theirembedded challenges. Contact him at website is

Reader Response

I take issue with but one statement in this column:
"Oddly, though, the charts are still crude, many ofthese remote islands based on surveys from the 19thcentury. It's ironic that the cheap little GPS is farmore accurate than the charts produced at greatgovernment expense."

While your GPS receiver might be cheap, I would bevery surprised if the sum cost of producing allmaritime charts in the 19th century approaches thecost of deploying (and maintaining) the GPS satellitenetwork for the last 30 years (it is difficult todetermine the cost of initially deploying theconstellation since it was a military project, butmaintenance has run around $400M USD per year since1978 for a total maintenance expenditure to date ofaround $10B USD).

So while the GPS is indeed more accurate than the 19thcentury charts, it was provided (as common sense woulddictate) at *greater* government expense than theolder charts.

There's no such thing as a free lunch Jack; rememberthis the next time you pay your federal income taxes(which is what actually provided the accurate positiondata you speak so fondly of - not the $49.95 you paidfor the receiver :-).

- Rennie AllenS/W Engineer

Jack,I agree -- the embedded technology has made manythings a whole lot easier. The big problem we all faceis what we do when (if?) the technology fails. I wasjust reading recently about a problem with a lot ofnew (and some old) airplane pilots, who, because ofthe accuracy and simplicity of GPS, have not developedtheir "dead reckoning" skills sufficiently. When theGPS occasionally fails, they're in trouble. Thesolution, of course, is redundancy. The electronicsare so cheap, you can have two or three of somethingas backups. It would be hard to go back to slide rulesand sextants!

- Dave Telling

I just wanted to tell you that I appreciate yousharing your gift for writing. You paint a wonderfulmental picture and it is a pleasure to read yourarticles. I am an up-and-coming embedded systemsprogrammer and your articles are inspiring. May theseas be calm and the wind be at your back :)

- Steve Broderick

I think that you have exactly the right attitude.Embedded micros do an incredible amount of such asmall cost. The 'on the mark' part is that you areaware of what they do, what their shortcomings are,and what your options are if they fail.

- Steve Nordhaus

Your conclusion regarding the proliferation ofembedded systems in our world leads my thoughts backto an earlier article of yours regarding certificationof software developers. Your GPS could easily providea location that was in error by a few hundred metres(perhaps causing you to run aground), due to asoftware error, and you would be none the wiser. Evena redundant GPS from the same manufacturer wouldlikely carry the same flaw, so calibrating one againstthe other would be useless.

The general masses who blindly trust technology (fortheir pacemakers, ABS brakes, toaster ovens, etc.) areat the mercy of an uncertified "profession" who faceno professional repercussion for a product createdwith questionable ethical input, where cost andschedule become more important than public safety.

- Diane Farish

Copyright 2005 (c) CMP Media LLC ###

No comments: