Page 19 - The Art of Designing Embedded Systems

6 THE ART OF DESIGNING EMBEDDED SYSTEMS

When the pressure heats up-the very time when sticking to a system that
works is most needed-most succumb to the temptation to drop the sys-
tems and just crank out code.

As you’re boarding a plane you overhear the pilot tell his right-
seater, “We’re a bit late today; let’s skip the take-off checklist.” Ab-
surd? Sure. Yet this is precisely the tack we take as soon as deadlines
loom; we abandon all discipline in a misguided attempt to beat our
code into submission.

Any Idiot Can Write Code
In their studies of programmer productivity, Tom DeMarco and Tim
Lister found that all things being equal, programmers with a mere
6 months of experience typically perform as well as those with a year, a
decade, or more.
As we developers age we get more experience-but usually the same
experience, repeated time after time. As our careers progress we justify our
escalating salaries by our perceived increasing wisdom and effectiveness.
Yet the data suggests that the value ofexperience is a myth.
Unless we’re prepared to find new and better ways to create
firmware, and until we implement these improved methods, we’re no more
than a step above the wild-eyed teen-aged guru who lives on Coke and
Twinkies while churning out astonishing amounts of code.
Any idiot can create code; professionals find ways to consistently
create high-quality sofhvare on time and on budget.

Firmware Is the Most Expensive Thing
in the Universe

Norman Augustine, former CEO of Lockheed Martin, tells a reveal-
ing story about a problem encountered by the defense community. A high-
performance fighter aircraft is a delicate balance of conflicting needs: fuel
range versus performance. Speed versus weight. It seemed that by the late
1970s fighters were at about as heavy as they’d ever be. Contractors, al-
ways pursuing larger profits, looked in vain for something they could add
that cost a lot, but that weighed nothing.
The answer: firmware. Infinite cost, zero mass. Avionics now ac-
counts for more than 40% of a fighter’s cost.