XBox 360 Backwards Compatibility
on 05.17.05, 10:50am in software • comments (8)
[Dare Obasanjo] It was announced at E3 this week that XBox 360 will be backwards compatible with the original XBox. My good friend, Michael Brundage, was the dev for this feature. Read about XBox Backwards Compatibility from the horses mouth.
Without a doubt, Michael is one of the smartest guys I know. And having backwards compatibility with the original XBox would take nothing short of a rocket scientist to get it done. Oh wait, he is a rocket scientist. Well, he worked at NASA, so that’s close enough for me.
JeffMc (May 17, 2005 @ 8:27 pm)
Well, if XBOX 360 is using the old PowerPC port I worked on, and they use Virtual PC’s core engine, I cannot see why it wouldn’t work. AME’s have always been the stalwart of changing architectures and still letting people run older software:
eg:
RSX-11M on VMS
Vax/VMS on Alpha/VMS
Win16 on NT 3.1
Win32 X86 on Alpha/NT
Classic on OS X
l.m.orchard (May 18, 2005 @ 3:28 am)
From what Michael wrote, it doesn’t sound like VPC is involved: “For example, Virtual PC for Mac is great for many tasks, but gaming isn’t one of them.”
I suppose that doesn’t rule out using some stripped down core of it, but it sounds like he did something entirely different.
jeffmc (May 18, 2005 @ 10:57 am)
Oh, I agree on the whole of VPC. It is sort of like what SoftPC (Virtual PC’s granddad) did on WOW in NT 3.1. The core execution unit was there, but all WIn16 functions thunked into core functions. Sort of like SavaJe did with Java. We might have had Java as the only API, but we kept 90% of stuff out of the bytecode interpreter and into native methods. That’s why gaming on SavaJe OS is pretty good, because all the graphics are native, and the 3D engine is native.
I could see them doing something similar to the XBOX AME (Applications Migration Environment). Basically all graphics calls are thunked into native and the VPC cpu core is there (similar to SavaJe’s byte code interpreter) to handle stuff than cannot be thunked. (NT’s original WOW did this too)
Jeff Atwood (May 18, 2005 @ 11:57 am)
As I understand it, 360 will *only* be backwards compatible with a select list of Xbox1 titles. This is probably a smart move on their part, and I agree that given the specs emulation will be very very difficult. I’m surprised they’re able to do it at all.
General rule of thumb is that you need ten times the computing power of the original platform for emulation without coding genius. If you’re a Michael Abrash, then maybe 5x as much. But either way, a lot!
jeffmc (May 20, 2005 @ 11:51 am)
Well it looks like backwards compatibility is via recompile… sigh…
http://www.gamesindustry.biz/news.php?aid=8996
Steve (May 20, 2005 @ 1:25 pm)
Actually, that’s completely false.
http://www.majornelson.com/2005/05/19/no-you-do-not-need-to-recompile-your-xbox-games/
jeffmc (May 20, 2005 @ 10:18 pm)
Forgot, you are always right
Steve (May 21, 2005 @ 7:43 am)
It’s not about being right or wrong, its just about being accurate.