Partially-bad chips; was: repairing early HP calcs
cclist at sydex.com
Mon Dec 19 19:52:21 CST 2005
On 12/20/2005 at 12:15 AM ard at p850ug1.demon.co.uk wrote:
>I remember a UK company called Bi-Pak. They bought up defective ICs,
>tested them , and sold them. They did sell things like TTL quad-gate
>packages with only 3 good gates. Problem was, as we all found, those 3
>gates quickly failed in use.
Back in the days when DRAM was precious, Intel had some "8Kx1" DRAMs that
were really "half good" 16K parts. You used the "-x" digit to determine
which half to use. I don't know if these were in general circulation, but
the sales engineers were passing them out to customers working on designs.
I may still have one or two kicking around that I found actually had 16K
worth of usable bits, providing they weren't run too fast.
And there was bubble memory with a flaw map.
Aren't some (or all) high-density DRAMs now made with extra rows and colums
to improve yields?
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