Subject: Re: RE: "viral" (was RE: Licensing options for firmware)
From: Michael R. Bernstein <>
Date: Wed, 6 Apr 2005 13:59:12 -0400

> From: "Anderson, Kelly" <>
> As a relative newbie to the open source concept, I actually appreciate
> the term viral as I find it more descriptive of what the GPL is all
> about than the more obscure term "copyleft". [snip] When I heard the term
> viral, I "got it" and understood the underlying premise more clearly.
> [snip] "viral" is an accurate and meaning-filled word for those of us who
> haven't spent the last ten years studying the nuances of every open
> source license. Copyleft doesn't carry the same amount of meaning for
> the general public.

While the term 'viral' certainly gives a very rough and visceral first approximation
for the effects of reciprocal licenses like the GPL, it also carries a lot of unfortunate
baggage, and does, in very short order, lead to misapprehensions regarding the relevant
rights and obligations.

Mainly, it conveys the impression (which has been exploited by various proprietary software
vendors) that these licenses can 'infect' other code, simply by coming into contact
with it. I've actually had to disabuse business folk of the notion that their in-house
code would have to be GPL-licensed if it was simply on the same physical server as GNU/Linux.

Infection simply isn't the appropriate metaphor here. Inheritance is.

Generally speaking, only code that is *derived* from reciprocally licensed code must
be similarly licensed. Even code that is combined with GPL code can remain under another
license when it is separately distributed (at least, usefully so. This isn't a loophole
for creating works that for all intents and purposes depend on the GPL code for their
utility). The best single word that would describe this would I think be 'chimaeral',
but who the heck would actually understand that?

And even then the metaphor breaks down, because derivative code that is never distributed
(ie. private modifications) are not (usually) required to be licensed under the original
code's license.

So you see, the term 'viral', as popular as it is, isn't very useful.

- Michael Bernstein