Say Jack,

Now THERE"s a good rule of thumb!  I'm in overload too (must be all the gray
hair [what's left of it]).

Bob Landman
H&L


-----Original Message-----
From: Jack Olson <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: May 10, 1999 12:27 PM
Subject: Re: [DC] Unconnected inner-layer pads


>On the other hand, it is difficult for the average designer working under
>deadline pressure to keep up with every facet of the industry, because there
>is SO MUCH scientific information out there.
>
>I am in complete agreement that one should question "rules of thumb" and
>reasons given "because we've always done it this way", because there has to
>be something behind it. Without knowing the foundation its hard to know the
>importance of it and under what conditions it can be considered a
>"trade-off" to a more important guideline or rule when designs get more
>complex.
>But my feeble brain can't hold too much more, its almost full. When I read a
>report I tend to summarize the findings into an easy "rule of thumb" that I
>can remember. The problem is that later when the subject comes up again, I
>only remember the guideline, not all the facts that supported it, so it is
>difficult to prove.
>
>So while I get frustrated when people spew rules at me without knowing why
>they are the way they are, I can understand how it happens and at least have
>a starting place for where to start looking. (Thanks for responding)
>
>onward thru the fog...
>Jack
>
>                -----Original Message-----
>                From:   Abd ul-Rahman Lomax [mailto:[log in to unmask]]
>                Sent:   Friday, May 07, 1999 9:18 PM
>                Subject:        Re: Unconnected inner-layer pads
>
>                I've noticed for years that there is a paucity of truly
>scientific
>                information regarding many areas of P.C. Design. Many items
>of "common
>                wisdom" are really someone's bright idea that might be true
>and might not
>                be true. In genuine science, theory takes a back seat to
>actual experiment,
>                and a scientific report would never say that something
>"should" always be
>                done. Rather it would simply report how varying one item
>under specified
>                conditions affected subsequent experience or measurement.
>
>
>
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