On Mon, 12 Jan 2009 23:07:02 -0500, kony wrote:

Come to think of it, there was very little that had more
than 2 layers before '80, so if that is where your supposed
experience comes from, suddenly it all starts to make sense.

DimBulb is certainly AlwaysWrong, but the above is simply bull****.
Perhaps in your little corner of the world you were still using
phenolic substrates too but others had moved on long before. We were
using upwards of a hundred layers (96, IIRC) on system backplanes and
easily eight layers (4P-4S) on plug-in cards well before '80 (the
latter were old hat when I started in '74). I haven't done anyting as
simple as two layers since college projects, and that was limited by
our wierd method (sides were cut individually on a lathe then
laminated).