There's some pretty famous "signs" that companies would put into their chips to show that it was blatently stolen. Also at some point it became a game:
What's fascinating is that you can basically run a country with little to no "actual" development of computer hardware, and just have an entire industry around "copying" to keep yourself up to date (or a few years behind at most).
This is pretty evident with China of the past few years in military tech, and now they are starting to leap frog (See engine issues with their new fighter, and how they are almost there but not quite. Russia is unwilling to sell them newer engines for fear of copying essentially)
Intel 8080A die photo:
580BM80A die photo:
I am not an expert in CPU design, so please correct me if i am wrong, but chips look rather different (at least Intel logo was removed on the 580BM80A die). Could it be that 580BM80A implements Intel's ISA, but actual CPU architecture is of their own? And could we call it a "copy"/"replica" if so? Like could we say that AMD CPUs are replicas of Intel CPUs, because they implement the same ISA?
I was skeptical at first, but I think it's possible that the Russian chip is a different implementation, and not just the same circuitry with the layout re-done for their process. It would require a closer look at the circuitry to determine for sure.
For the first link, removing https will avoid the expired certificate warning: http://vintageteardown.com/wp-content/uploads/2018/04/Intel8...
For the East German Z80 clone U880 there are some wild stories of how the secret service stole blueprints from Zilog, but the more believable version of the story is that some chips were smuggled over the border that had simply been bought in West German electronics stores. The East German Z80 version had definitely been reverse engineered - not simply cloned - because the U880 has a slightly different undocumented behaviour (for instance, the undocumented X and Y flags behave differently than on a real Z80), also apparently the Z80 has various 'trap transistors' which prevent that the mask can simply be cloned, those trap transistors had to be found and fixed (I guess this was the reason why the U880 project was delayed by a year or so).
The much bigger problem than reverse engineering the chips was setting up manufacturing anyway. For East Germany this definitely happened with secret service support. The story goes that a small chip manufacturing company was set up in West Germany, which soon after declared bancrupty with the entire manufacturing equipment sold off to another company somewhere abroad. "Somehow" that equipment disappeared en route and showed up in East Germany a few months later.
For comparison original 8080A: http://retrokolekcja.pl/zdjecia/MCY7880%20struktura%20ITE.jp...
Polish MCY7880: http://retrokolekcja.pl/zdjecia/MCY7880%20struktura%20ITE.jp...
Russian KR580BM80: http://retrokolekcja.pl/zdjecia/MCY7880_zsrr.jpg
And the absolutely amazing gem. In 1983 legendary science education TV program SONDA documented design and manufacturing of first batches in a humorous lets bake a cake fashion. Paper plotters, light pens, developing/rinsing dies by hand, electron miscroscope debugging, the whole nine yards!
part 1 https://www.youtube.com/watch?v=AJGp7keIA_o
part 2 https://www.youtube.com/watch?v=KHl6m93Hay0
part 3 https://www.youtube.com/watch?v=rcOTwkT-PDU
Its amazing anything worked considering really spartan conditions.
I've found a few of these traps in the Z-80, and they were placed very maliciously. The circuit appears reasonable and correct, but fails in subtle ways.
https://retrocomputing.stackexchange.com/questions/11143/in-... references "Zilog oral history" and poses the question, but there isn't a strong answer other than the link to the above.
The oral history document referenced is: http://archive.computerhistory.org/resources/access/text/201... . The discussion of traps begins on page 101.
This doesn't sound right to me. For one thing, the idea that you need to simulate analog effects in order to properly emulate an instruction cache sort of flies in the face of my (admittedly amateur) understanding of reasonable chip design. For another, that'd imply that the CMOS versions of the 68K function differently than the HMOS ones, and I can't find any indication of that. Finally, as far as I know the 68000 doesn't have an instruction cache!
But beyond that, the core has already been ported to MiSTer, which would be much more enjoyable to use: https://github.com/MiSTer-devel/Altair8800_Mister
Didn't IBM have an ALU design that were more harden again calculation errors?
Setun used balanced ternary logic instead of binary logic. Each trit could be -1, 0, or +1. For numeric values, there was no need to store a sign, since the sign of a number would be inherent in its ternary value.
Then the Soviets decided that it would be easier and faster to just copy western computers, and the concept wasn't developed any further.
To the best of my knowledge, BESM-6 and Elbrus were not clones
I'm genuinely confused what is meant by this in practice. Like some sort of redundant ALU architecture or rad hard encapsulation?
this might be what is referenced?
I did work as a CPU logic desiger at Amdahl. We had full parity through-checking, so an ALU intermittent logic error would raise a parity exception. Certainly IBM would have had the same, it was standard SOTA reliability logic for the era of mainframes when I was a designer.