D8087 Datecodes and copyright - is this a fake?

[debs3759]

I'm going through a large number of processors that I am scanning (preparing an enormous update for my site...) and came across a D8087 that I'm unsure about.

I've seen examples of the 8087 with the following copyrights:

1980 (the original)
'80, '81 (I've only seen on C8087-3, C8087-4, C8087-6 and MC8087/B so far)
1982 (I've only seen on C8087-3)
1980, 1984 (and '80 '84)

I have always assumed (but never checked) that when a chip is produced, the print would show the most up-to-date copyright. This would mean that any produced after 1984 would have "1980, 1984" or "'80 '84" for the copyright. I have one that is a lot later than this but only copyrighted 1980.

I'm not always sure about datecodes on the bottom of a chip, so am not sure whether to look at the "931" as the datecode, or the string above it. If the 931, then it's week 31, 1989, which ties in with the week 33, 1989 on the top of the chip. This is well after 1984, leading me to wonder if this might be fake? Did Intel still produce them with the older core after 1984, explaining the 1980 copyright? Is there a known/documented reason why they would not use the 1984 copyright (or the later core) at such a late date?

I'm hoping that I'm missing something here, and that this is what it appears to be (rather, what it would have appeared to be if I hadn't documented copyrights for all examples I had seen in the past)

[JAC]

[debs3759]

I know it's not uncommon to see such a big difference between between copyright and the date of production. I was asking whether it is common for a chip to skip back 4 cores and 8 years (1989 is at least 8 years since the core copyrighted in 1981 was produced, and 3 cores were skipped back over to use a 1980 mask).

What doesn't make sense to you about the date markings? Is it the same thing I was saying doesn't make sense? If so, do you have any ideas? I also can't see a reason for it to be a fake, as it would be the cheapest 8087 they could have faked. I'm merely wondering what others think, based on the copyright dates and the production date, before I put it on my site.

I guess it will be easier when I eventually get round to setting up an 8086 system that I could test it on

[JAC]

I am not 100% sure of the formatting of the bottom numbers when they are long like that. If you drop the first number of the long line on the bottom then the number make sense.. 1988 week 42. It ties in with the top numbers and the three digit code that I take as another date.


It ties in with this one for example..




and to cover one of your other points with another example, there are 287's copyrighted in '86 and '83!!

[debs3759]

In that case, I will asume that it wasn't uncommon back then for Intel to use an older core (or mask) for whatever reason. I have always tended to assume that a new core (bug fix...) would have always meant that the older core (with known problems) would be discontinued. I was unsure because it is the first time I have thought to check it

Thanks for your comments

[CPUShack]