Subject: Re: $8 million for self-parking charge (Kuenning, RISKS-24.30)

Geoff Kuenning reported an *LA Times* humor photograph featuring a self-pay
parking kiosk with a mis-set date of 16 May 1943, showing an amount due of
$8,082,022.84.

And he commented, "Sanity checking, you ask?  Not bloody likely.  An
auxiliary display shows the fee in larger characters; it reads 8.1E+6.  When
you have an programmer so clueless as to calculate money values in floating
point, there is little hope for subtleties like sanity checking."

And continued, "As a side point, I'm fascinated that things like parking
kiosks now use chips powerful enough to have floating-point support, at
least as a library.  A 4-bitter would be adequate for the task, though it's
not clear to me that this particular programmer could have written the code
needed to compute the fee on a 4-bit machine."

Assuming that the photo is genuine, it seems at least plausible that the
programmer used a software library for calculating cost based on elapsed
time rather than explicitly using floating point. Regarding the chip's
bitness, unless the programmer is writing assembler code (risky business for
such a mundane application), it seems unlikely that modern programming
languages are supported by 4-bitters.

Sanity check? Sure, programming insanity is easily detected in
hindsight. The kiosk should have refused a date earlier than some epoch. But
what was the 1943 date? The kiosk's "current" date? The date a car was
supposedly parked? The fee calculation might have refused to present an
amount greater than some number. But what specs was the programmer coding
from? What government agency requirements were the specs derived from? Why
didn't a simple test case involve feeding the kiosk a prehistoric date?

I guess the computer risk is debugging and proposing a solution based on a
photograph of an incorrect result, not to mention blaming the anonymous
programmer for (perhaps) just coding to design. And the manufacturer for
using current technology vs. (perhaps) obscure and hard-to-program
minimalist hardware.

Though, of course, there's likely a big-city market (New York, certainly)
for parking meters displaying fees in floating point.

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