Codename Vejle: Xbox 360 S combined CPU/GPU

[Shifty Geezer]

I have to wonder if Sony cares about BC at all at this point. Their new strategy seems to be to sell old games as HD remixes (God of War collection) or maybe as DLC.

That's exactly the reason to want BB. Not for people to play the games they've bought, but for people to buy the same games again. Think how many Nintendo fans are buying on Wii the same games they bought 10-20 years ago on (S)NES... (okay, I have no numbers for that at all!)

 

[3dilettante]

Can anyone explain why was the "front bus emulation" needed? What exactly would break? I doubt anyone is making their games depend on such low-level timing, but who knows?

I'm not certain a game can be coded to that level, but any bit of the system that relied on the bus, from how the cores arbitrate for resources or communicate with the GPU or northbridge could be affected by a change in the latencies or protocols of the FSB.

Unexpected holes in the system's protocols could open up, such as updates that suddenly take much less time relative to other system messages that could lead to incorrect execution or a system-halting error.
If the northbridge, GPU, and CPU were revalidated and everything they used to communicate was was checked and potentially re-engineerd as well, this would be avoided.
Then again, that is an awful lot of work for a platform whose major components would not be upgraded, so this fancy new bus would at best insert a chance for serious flaws with little upside.

It sounds simpler to me to just validate that the new bus acts exactly like the old one, instead of trying to test how everything else needs to be changed to match a different bus.

 

[Rangers]

That's exactly the reason to want BB. Not for people to play the games they've bought, but for people to buy the same games again. Think how many Nintendo fans are buying on Wii the same games they bought 10-20 years ago on (S)NES... (okay, I have no numbers for that at all!)

Wait what?

I think of BC as "you can play your old discs in your new console". Not you have to buy them again as DLC. Different tactic. I just remember when Sony nixed BC in the new PS3's people speculated it was so they could start eventually selling PS2 classics online. Which imo would be more "ported" than BC.

 

[Shifty Geezer]

If it's code native, it's BC. If it requires a rewrite of the code to work, it's a port. Sony selling PS2 classics on PSN would require rewriting them, which is in part why it hasn't happened. If PS3 was BC with PS2, we could still play our disc games of course, but Sony would also be selling the PS2 library online.

 

[Grall]

I'm curious - what is it that would break existing games?

Like already stated in the thread, it's probably not so much what they know would specifically cause games to break; there's probably no real (known) danger of anything breaking. No, it's rather risk elimination. Why fuck with that which isn't broken for no gain? Sure, some games would perhaps gain an (probably unperceptible) amount of performance on newer hardware only, but the games still have to run on the 30something million existing units so it doesn't matter.

As for what COULD potentially break games by changing the hardware - and I'm just speculating here - but THIS is a definitive danger. Weird bugs can happen in code if a sequence of events don't happen the way you expect them to - and it might only be in very rare cases, making debugging both a pain, and very expensive.

You don't want to debug old code for new hardware; it's a waste of money. Like your customers, you want everything to just work like expected, so it's better to engineer the system that way from the ground up just to be on the safe side.