Subject: Re: Hal's new white paper - Free Software/Public Sector
From: (David N. Welton)
Date: 23 Mar 2004 15:52:43 +0100

"Stephen J. Turnbull" <> writes:

> >>>>> "David" == David N Welton <> writes:

>         A consumer located at x [0, 1] gets a net utility from
>         buying the closed source software of

>                                 Uc = v - tx - p,

>         Similarly, the consumer's net utility from adopting OSS is

>                                Uo = v - t(1 - x).

>     David> Why should free software necessarily be the inverse of
>     David> the proprietary software?

> First, you need to understand the metaphor---see Jerry Dwyer's post.

He says:

Jerry> Hence, the apparent inverseness of commercial and open-source
Jerry> software in terms of transportation cost, where one cost is
Jerry> t(x) and the other is t(1-x), where x is the distance to zero
Jerry> and 1-x is the distance to the other end of the line -- unity.

I guess what I'm not getting with that is why there is any
relationship between the transportation costs of the two?  That's not
related at all to whether the software is free or proprietary.

> If you do understand the metaphor but are still wondering, then
> there's a technical detail.  It's a convenient simplification.  You
> could have "z" be the degree to which your practices are adapted to
> proprietary software and "y" be the degree for free software, with
> "t" being the cost of adaptation.  Then with "v" being the maximum
> value of perfectly adapted practices and software:

> Uc = v - tx - p,    Uo = v - ty

> The decision rule is "Buy OSS iff Uo > Uc", ie

> 0 < Uo - Uc = [v - ty] - [v - tz - p] = t(z - y) + p

> It turns out that in this kind of analysis, both z and y appear
> _only_ in the form (z - y).  So s/(z - y)/x/g simplifies all the
> formulae with no cost in realism.

Ahhh, I think I get it.  The 'x' is present, but there isn't anything
that says it isn't .5 (or nearby), or even "in favor" of free

David N. Welton
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