24 Nov
2014
24 Nov
'14
5:59 p.m.
On 11/23/2014 02:53 PM, John Foust wrote:
At 09:28 PM 11/21/2014, William Donzelli wrote:
I'm VERY skeptical of this one! First, I know IBM went to
great lengths at some time in
the early 60's to figure out how to make reliable computers
with a LOT less gold than
the traditional wisdom required. As far as I know, all
360's had a LOT less gold in
them than similar-sized machines from other makers at the
same time.
On the other hand, a lot of gear from the mid-60's actually
used gold as the etch
resist on the circuit boards. I have some examples of
that. The traces of the
boards are totally plated with gold!
Jon
The NASA model 67 reportedly had 66 ounces of
gold in the CPU. Even an
early model 30 could have 8 or 9.
How could a CPU have four-and-a-half pounds of
gold?
24 Nov
24 Nov
6:32 p.m.
I'm VERY skeptical of this one! First, I know IBM
went to great lengths at
some time in
the early 60's to figure out how to make reliable computers with a LOT less
gold than
the traditional wisdom required. As far as I know, all 360's had a LOT less
gold in
them than similar-sized machines from other makers at the same time.
That is not true. Early S/360 had a lot of gold in the backplane pins,
later ones did not. This is why IBM stuff from 1970 or so is such a
mixed bag - some machines had the cost saving tinned backplanes, some
still had the gold.
Looking at one of the gold backplanes, you will see that the plating
is thick - the gold is very deep and dull. Over that many pins, that
is a very large surface area. Doing a thick plate over a large
effective surface area takes a LOT of metal. To give a more modern
perspective on things - how much gold do you think is in a Pentium Pro
microprocessor? Thick plate over a large surface area...go look it up,
and you will probably be surprised. Then do some back of the napkin
calculations on the surface area of the PPro, compared to thousands
upon thousands of pins in a 2075...
--
Will
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elson＠pico-systems.com -
wdonzelli＠gmail.com