gEDA-dev: Question about Gerber output of PCB

[Stuart Brorson]

>> INCH,TZ
>> My question:   Umm, is it correct syntax to just say "INCH" on a line?
>
> Don't confuse gerber photoplotter files with excellon drill files -
> the format is similar in style, but different in details.
>
> See http://www.excellon.com/manuals/program.htm

Hmmmm, good reference.  OK, I see that INCH is mentioned in there.

OTOH, I haven't come across it anywhere else.  This webpage also uses
M72 codes:

http://www.forelec.ch/www/norme_excellon.htm

I wonder if the INCH thing is a proprietary extension of Excellon's?
Or maybe not....

FWIW, gerbv would not recognize INCH in a drill file, as far as I can
tell.  Its parser will key off the "IN" at the beginning of the
string, and will then assume the Image Name is "CH".  However, since
its default unit seems to be inches, either this doesn't cause a 
problem or is perhaps a latent bug....

Stuart