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Date: Wed, 23 Apr 2014 13:09:39 -0400
Message-Id: <201404231709.s3NH9d8n026117@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: geda-user AT delorie DOT com
In-reply-to:
	<CAHBVutA1MLS2U=UzG5tWvp1XhohfoyjKnrbdZhMS7mM2Zv8RWQ AT mail DOT gmail DOT com>
	(message from Filippo Micheletti on Wed, 23 Apr 2014 18:40:04 +0200)
Subject: Re: [geda-user] again about pcb file format
References: <CAHBVutA1MLS2U=UzG5tWvp1XhohfoyjKnrbdZhMS7mM2Zv8RWQ AT mail DOT gmail DOT com>
Reply-To: geda-user AT delorie DOT com


> the unit (mil or mm) but I cannot understand the behavior of pcb... in fact

It looks at its internal value (which is in nanometers) and tries to
determine whether the origin of that valua was inch or meter based,
then applies a suitable conversion.  This, in theory, makes the file
easier to read and preserves the values more accurately across
save/load commands.  Without this, metric designs would lose precision
when saved.

PCB has been able to read files formatted like this for a long time now.

> Is there a place where one can see a log of changes in .pcb file format
> through pcb versions?

You can read the ChangeLog that comes with the PCB sources, but that's
going to have *all* the changes.