PS5 Backwards Compatibility could already be in the works by the lead architect of the PS4

More possible news has surfaced about the super secret development of the PS5, Sony's next-gen follow up console to the hugely successful PS4, and this latest rumour is one of the most exciting things we've heard yet. 

As first spotted by hokanko-alt, Sony recently registered a patent with the Japan Patent Office to protect a new method that lets its devices determine whether an application is a legacy application or not. 

In technical jargon, "legacy applications" usually refer to those programs that were previously designed for older hardware, and this patent describes a CPU identification algorithm that essentially allows legacy software to run on Sony's newer devices. 

https://www.gamesradar.com/ps5-backwards-compatibility-could-be-already-in-the-works-by-the-lead-architect-of-the-ps4/

I guess that's a plus for those that care about having BC, but i'm not one of those people. I could maybe see myself using it for the first few months after release, that'd be about it.

Could just be for PS4 games on PS Now.

Will threat as rumor as usual but yes there is possibility for BC, but no certainty yet.

Given the fact the next Xbox will definitely have BC I thinks it’s smart for Sony to also have it, all pros and no cons really.

Yep.   I would say PS5 will have BC, can't be otherwise.

Since B/C is going to be industry standard going forward, and across multiple form factors at that, I don't really think Sony has a choice if they want to remain a player in this space.

There have been a lot of signs that PS5 will have B/C. I think the only question now is how far will it go. Sony will have to move away from Cell/Nvidia based servers for PS3 games on PS Now. That will likely mean PS3 games will end up emulated on Epyc/Radeon based servers. This will be the same tech we have in PS5, so there is really no reason PS5 should not include PS3 B/C as well.

Then theire is the next gen Phone/Portable as well. That will need access to PS3 and PS4 titles as well. Sony could win big if they announce all of your Digital PS3 and PS4 titles will be playable on PS5 and PS5 Phone day one.

Well isn't PS5 just next gen PC parts essentially? PS4 is current gen PC parts, so in theory it won't be hard to make the games work. Just like games on steam work lol.

Not quite, since hardware and software design are much more specialized than PC, and even there you might have compatibility issues between operating systems and hardware configurations. The fact that they are both x86 isn't a guarantee that games will run going forward. It depends mainly on whether the CPU / GPU hardware architecture fully encompasses features that were present in former hardware. Say that the Navi GPU axes some features that existed on Polaris / Southern Islands GPUs. Then suddenly it becomes a much more complicated issue to be backwards compatible. Same for the CPU. That's why backwards compatibility needs to be a conscious decision on both hardware and software design. The PS3 for instance was an even more specialized design so there's little chance a hypothetical modern PowerPC + modern Nvidia GPU console could natively run the code (without emulation) that used to run in the Cell BE and the RSX.

If PS5 is not fully backwards compatible to PS4 then it's specifically by design to prohibit it.