> Two programs can work the same way and still be distinct, independently developed works. This is especially true of programs that have to work in certain ways in order to be compatible.
This is like if a state lottery employee would claim "oh, but there are other recorded cases of people winning the lottery 2 times" to justify why he in particular won it 300 times in a row.
It is one thing for two similar implementations to appear from different sources (and a rather probable thing at that). What I said is that it is impossible for two _identical_ implementations to appear from two different sources, for anything but the most trivial of programs.
Again, a decompiled program will not only work the same way as the original in the observable external behavior, it will also be identical even in its internal behavior (state machines, and everything). If you even admit that were literally looking at the first implementation while you were implementing the second one, or worse, that in fact it is an automated translation of it.... how can you even start to justify having a legal case? What do you exactly think copyright is for?
> If you did that and you didn't have a license, they'd sue you for trademark infringement.
FYI, this is _precisely_ what is actually allowed by the interoperability clause, at least in the EU. i.e. this "nintendo logo" trick was pointless back then and it is definitely pointless now. In simple terms, when there is _no other way_ to interoperate you are allowed to _violate copyright_ (i.e. re-distribute possibly copyrighted material without permission) to the extent that is required to allow this interoperability. For example, if company X decides to develop an encrypted protocol with a "proprietary" encryption algorithm, you may be allowed to re-distribute a subset of company X's encryption code (incl. key material) in order to talk with company X's hardware. This is allowed, and in fact my previous company used to do this (with utmost care).
But it does NOT mean that you can now re-distribute ALL of company X's software, use the entire firmware of company X's devices to create your own copycats, create tools to help others violate company X's copyright, or anything like. There's no way to interpret this provision in a way that allows you to free lunch.
Also note that even in this case you still _cannot_ (legally) use a trademark (e.g. you can't show the USB TM logo in your product's box), but no judge in the world will argue that using a hash of a logo as an encryption key is "using" the trademark. Laws are written for humans, not machines.
> https://en.wikipedia.org/wiki/Sega_v._Accolade
You keep posting this link even though many people have already told you it really doesn't mean what you think. I'm not an expert in US law, but even I can imagine that this case didn't really allow Accolade from suddenly being able to re-distribute Sega games nor their decompiled Sega game code. At most, it allowed them to use the decompiled Sega game code to develop their own Sega-hardware-compatible games, something which (unsurprisingly) looks very familiar to what I was explaining above about how it works in the EU.
> Such was the wonderful world before the DMCA and its criminalization of "circumvention".
DMCA has very little to do with anything of this. You still cannot violate copyright even if there was nothing to circumvent.
> The hard part isn't explaining things to judges, it's coming up with the fortunes necessary to pay lawyers to do it. That's why the big corporations have the advantage.
Let me guess: you are one of those who believe big corporations will have a harder time if copyright is abolished.
Let me tell you what will happen: big corporations will immediately self-appropriate all software from "small" corporations. Almost all open source software will disappear as a result (know many FLOSS people who are happy releasing PD software? not even BSD people are -- they require attribution). And instead of getting the "oh all software is free world" that you expect, you will instead get a world of incredibly invasive DRM schemas, complicated and expensive hardware protection systems, and binary code guarded behind closed doors in big farms and you can never dream of executing outside corporate security eyes. Reverse engineering it will still be possible of course... but only if you have infinite resources, like those of another mega-corp, with an army of engineers at your disposal.
I know this because I have seen it -- this is the world of industrial "our entire million dollar business is basically one algorithm" CAD software, where your competitors do not really care about mortal nuisances such as copyright. What Sega, Nintendo, etc. do as DRM is basically just child's play so that piracy doesn't become too widespread, but nothing more.
So not only will the bigger fish still eat the smaller ones, you will not even have the courts to at least try to protect the medium size fish.