In The Trenches
Of course, the transformer
doesn't have to provide 2 amps. A 1.0
amp or 1.2 amp transformer could be
considered. It will also be less
There are a number of points
here. A conservative transformer
choice (2 amps) makes other parts of
the design non-conservative. The
specification of an RMS voltage ( 24
VAC) is not the specification of a
peak voltage ( 37. 3). Safety requires
the full understanding of every detail.
Cutting corners or carelessness is
simply unacceptable when safety
It is also interesting to note the
dance between target specifications
and performance specifications. We
make our design meet our target
specs by choosing parts with proper
performance specs. When we're
done, we'll have a product with performance specifications. Further, our
product may be used in another
product to meet its target specs and
so forth and so on.
First, stop laughing. There is
some truth in calling software
specifications an oxymoron. If you
don't believe this, read Microsoft's
"End User License Agreement." It is
With software, if it works, then it
meets specifications. There is no
easy way to determine if standard
engineering practice is employed.
There is usually no outside review
of the actual code. This is very
different from hardware. A circuit
board must not only work, but must
meet specific design rules (AKA
specifications) in regard to parts
placement, layout, trace widths,
trace spacing, hole size, and so
There are no equivalent rules for
software. There should be. There
have been attempts to analyze code
with software, but this has not been
generally accepted, nor, as I
understand it, is this software
The target specifications for
software become its performance
However, these are not the same.
The target specs say what the
product must do. The performance
specs say how well it must do it. I
have never seen actual performance
specifications for software, with the
exception of benchmark ratings. The
only way to compare similar software
packages is to actually try them,
Objective software standards are
not impossible to create or measure.
How about measuring the ratio of
branch to in-line statements or a
code-line to comment-line ratio?
What about providing the number of
standard library code-lines and the
number of custom code-lines? These
values would allow the comparison
of one program to another. It seems
to me that they would be useful
Unfortunately, I don't see this
The Root of All
One of the most common
sources of customer complaints
and legal action is because the
customer feels that the product
doesn't meet specifications: This
clock doesn't keep time. The radio
doesn't pick up my favorite station.
The air conditioning doesn't keep
the whole office cool. I want my
There will always be unhappy
people. However, your product
shouldn't make them that way.
Properly specifying your product can
go a long way in reducing these complaints.
Additionally, good specifications
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