a better analogy for the warranty discussion?

[Dick Dunn]

I think some of the discussion about quality and (unlimited) warranties is
getting sidetracked by the automobile analogy.  I understand the value of
an analogy, since we're really aiming at how the software world could be
re-shaped in some other mold, but I think we need a closer analogy.  John
DeArmond got more out of the analogy than I would have expected--but his
arguments fall short in a couple of places, as do the arguments of the
folks on the other side.  (It's not valid to say "software isn't a car;
therefore if we do <x> with cars we can't do <x> with software."  If the
analogy breaks down, it says neither yea nor nay.)  I'd like to suggest
that when the analogy gets weak, we abandon it or look for a better one,
rather than either:
	- continuing to stretch it without regard to the dissimilarity
		or
	- trying to reason backward that if the analogy breaks down, the
	  idea being advanced can't still hold for both items separately

One problem with cars is that they're physical objects which wear out in a
very real, direct, observable sense.  (A couple of people have pointed out
that software also "wears out"--but in such a different sense that although
I agree with the point, I don't think it supports the analogy.)

Another problem is that cars are bought and sold; software is licensed.

You might use books rather than cars to answer these two analogy
breakdowns.  The point of purchasing a book is usually for the contents
much more than for the embodiment.  You are licensing a copy of a written
work.  And while books do wear out, that's relatively rare.  The
information content remains.  Books also allow us to carry the red herring
argument about software, that "every defect was there from the start".  If
your encyclopedia says that the atomic number of Fe is 37, it's wrong; it's
a defect (a "bug") and was there from the start.  You have to be a little
careful about the scale between books and software; for example, the K&R
white book is about the equivalent of half a meg of source code.  Also,
prose is more forgiving--an error in number, tense, or mood of a verb
seldom produces a catastrophic misunderstanding.  Still, books can be a
useful analogy to software when more tangible mechanical objects don't
compare.

One of the major differences between software and cars is that there's a
very different class of interoperability.  I can drive a Toyota or a
Cadillac on the same road--if this were the world of software I'd only be
able to drive on Toyota roads, and if they didn't go where I wanted to go,
I'd have to buy a different kind of car!  One of my cynical observations
about software was the way some companies act as if "a dissatisfied cus-
tomer is better than no customer"--and one of the reasons is that the more
customers you've got, the more applications you'll get.  There's a
positive feedback. Market share means something very different.  (I could
launch off into more reasoning here, but it would only stretch the non-
analogy even further.:-)
-- 
Dick Dunn     rcd at ico.isc.com -or- ico!rcd       Boulder, CO   (303)449-2870
   ...Relax...don't worry...have a homebrew.