That only applied to some of the darker ceramics and early parts
were the white. They still had to remove or reduce the gold used
in the bond wire and lead frames even for plastic. What drove the
price of ceramic way up is ram and cpu prodution rates really
jumped up from 1978 to 1984 and the production of ceramic packages
could not keep pace.
Plastic was always used for ram, and lower in cost. The problem was
the early gray silicone plastics were far from hermetic. There would be
several generations of the black stuff in an attempt to make the plastic
less absorptive of moisture while trying better methods of passivating
the die. Then there was the matter of disapating the heat. Even as
late as 1984 the failure rates for the D416/4116 dynamic and 2114
and 2167 static parts was noteably higher for plastic than ceramic.
I use those cases as they were mature parts by then and still plastic
was viewed as less reliable though far lower in cost.
Allison
-----Original Message-----
From: Bob Shannon <bshannon_at_tiac.net>
To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
Date: Monday, November 19, 2001 10:22 PM
Subject: Re: Intel C8080A chip brings $565 on EBAY
>In my experiance, very early chips used a purple ceramic with a high
thorium
>content causing the distinctive color. Unfortunatley, this thorium
emits low
>level
>particles that cause soft errors, which became apparent in the early
days of DRAM.
>
>This drove a change in ceramic processing and costs, pointing the way
towards
>todays plastic packages.
>
>Sellam Ismail wrote:
>
>> On Mon, 19 Nov 2001, John Galt wrote:
>>
>> > As far as the color, chip collectors refer to that color chip as
>> > "purple". If you look at it next to a normal "gray" CerDIP, you can
>> > see the difference. Besides, it would not have mattered had it been
>> > black. The fact is, it's not the white/gold color of a normal Intel
>> > C8080A. The printing on the chip is also somewhat different. My
>> > guess is it's a late run C8080A that was put in the same package
they
>> > used for some of the later C8085AH's.
>>
>> My questions is: why does this matter? Will researchers 50 years from
now
>> find the Purple one useful for any sort of study? What makes the
Purple
>> one special beyond just being a pretty if not questionable shade of
>> purple?
>>
>> Sellam Ismail Vintage Computer
Festival
>> ----------------------------------------------------------------------
--------
>> International Man of Intrigue and Danger
http://www.vintage.org
>
Received on Mon Nov 19 2001 - 21:58:38 GMT