Effective
Engineering
e-Newsletter
– 8/07/2008
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eN-080807:
What Horse’s Ass Said You Should Do It That Way?
By Tom
Dennis – President, Effective Engineering [tdennis@effectiveeng.com]
Have you ever asked
what horse’s ass said you have to do things a particular way? I recently
received an email from my old Bell Labs friend, George Scott, who forwarded
an email from another old friend, Emil Wrede, about an extreme example of
the impact of why things are done the way they are. It’s a story that has
endlessly made its way around the Internet, and I had seen it many times
before and chuckled, but George pointed out that could be good fodder for
one of my e-Newsletters, and he is absolutely right! So, here is the story,
unedited. Be sure to read the final paragraph: your understanding of it
will depend on the earlier part of the content:
The US
standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches.
That's an exceedingly odd number. Why was that gauge used?
Because that's the way they built them in
England, and English expatriates built the US railroads.
Why did the English build them like that?
Because the first rail lines were built by the same people who built the
pre-railroad tramways, and that's the gauge they used.
Why did 'they' use that gauge then?
Because the people who built the tramways used the same jigs and tools that
they used for building wagons, which used that wheel spacing.
Why did the wagons have that particular odd wheel spacing?
Well, if they tried to use any other spacing, the wagon wheels would break
on some of the old, long distance roads in England, because that's the
spacing of the wheel ruts.
So who built those old rutted roads?
Imperial Rome built the first long distance roads in Europe (and England)
for their legions. The roads have been used ever since.
And the ruts in the roads? Roman war
chariots formed the initial ruts, which everyone else had to match for fear
of destroying their wagon wheels. Since the chariots were made for
Imperial Rome, they were all alike in the matter of wheel spacing.
Therefore the United States standard railroad gauge of 4 feet, 8.5 inches is
derived from the original specifications for an Imperial Roman war chariot..
Bureaucracies live forever.
So the next time you are handed a Specification/Procedure/Process and wonder
'What horse's ass came up with it?' you may be exactly right. Imperial
Roman army chariots were made just wide enough to accommodate the rear ends
of two war horses (Two horses' asses.) Now, the twist to the story:
When you see a Space Shuttle sitting on its launch pad, there are two big
booster rockets attached to the sides of the main fuel tank. These are
solid rocket boosters, or SRB's. The SRB's are made by Thiokol at
their factory in Utah. The engineers who designed the SRB's would have
preferred to make them a bit fatter, but the SRB's had to be shipped by
train from the factory to the launch site. The railroad line from the
factory happens to run through a tunnel in the mountains, and the SRB's had
to fit through that tunnel. The tunnel is slightly wider than the
railroad track, and the railroad track, as you now know, is about as wide as
two horses' behinds.
So, a major Space Shuttle design feature of
what is arguably the world's most advanced transportation system was
determined over two thousand years ago by the width of a horse's ass.
And you thought being a horse's ass wasn't important? Ancient horse's
asses control almost everything ... of course!
OK, this really is an amusing story, and really is based on
history. It gives almost unprecedented meaning to the term “backwards
compatibility”. But what does this have to do with you as an engineer?
Well, let me count the ways!
► Someone designs a product (hardware, software, mechanical, or all of the
above) making some design decisions based on the limitations of the
technology that exists at that time. It was not even viewed as a limitation
at the time, just what made practical sense. Subsequent related products
must then contort themselves in extreme ways to satisfy the initial
arbitrary decisions for years to come. As an example, think about the
initial memory limitations in MS-DOS (due to the high cost of memory devices
at the time) and the contortions that went on for years to conform to the
limited memory allocations that were initially made. Think of all the
similar limitations you’ve been forced to live with in your product areas.
► You come up with an elegant design that efficiently and effectively
implements a solution to a problem that has troubled customers forever,
promising to simplify their lives in ways not thought possible, only to be
told by your management that in order to be compatible with some outdated
but critical internal systems (possibly not even related to the product
you’re designing), you simply can’t use your groundbreaking solution.
► You independently, and legally, reverse engineer a portion of
another company’s extremely successful but proprietary product, enabling you
to integrate that company’s product smoothly with your own, potentially
enhancing sales of your and their products, only to be told that you can’t
do it that way due to “potential” infringement concerns. As a
consequence, your elegant and ready solution is abandoned for a long “legal”
approach that is costly, time consuming, inelegant, and likely unsuccessful.
There are so many examples of having to live with someone else’s past
decisions. You must contort your software so that it will work compatibly
with Internet Explorer. You must force your product to comply even with
unused portions of an aging protocol standard. You must cripple a new
software product so that it can interoperate with another company’s
product. You are being forced to sell a new and dynamic product through an
old and dying sales channel, and missing the opportunity to open up new and
more profitable ones. Etc., etc.
“Do it this way because that’s the way things have always been done!”
is a phrase that has been said repeatedly in companies around the world,
often to the disdain of creative engineers. You’ve got to be backwards
compatible with this or that or the other thing. There is an old joke that
goes: “How was God able to create the world in just six days?”
Answer: “He didn’t have an installed base to worry about!”
As frustrating as this can be, sometimes it’s just the way it is, and the “unreasonable”
requirements are real and must be followed. Sometimes sanity can reign and
decisions to take a new and unfettered approach will be made. Still, even
in those cases, that “new and unfettered approach” will then become
the new “standard” that future designs must be backwards compatible
with. And so the cycle continues.
So, it’s not always about some horse’s ass who sets “unreasonable”
requirements for a product. Sometimes the horse’s ass is the
requirement!
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