RichC2

Right, they should basically just be creating a virtual machine running a Xbox 360 instead of the more traditional emulation methods, hopefully they do it right.

kgrogers1979

The FAQ someone posted in post #4571 makes it sound like emulation, so it is likely going to be exactly the same as the original Xbox emulator on the 360.

davidh777

That would be cool as I still have a number of unplayed 360 games like Red Dead Redemption and early Assassin's Creed.

fumanstan

It's definitely emulation, I was just saying that running it in a VM should help isolate it from sharing resources and running it on top of existing the existing XBox One instance. Basically I'm just assuming they can throw more power at it then the original XBox emulation on 360.

RichC2

Yep. That's all you can really hope for.

That said, outside of Splosion Man, Pac-man CE and Meat Boy, I don't think I'll be using it a whole lot.

Jay G.

I don't know if it will be exactly the same; the differences in hardware and software between the XBox One and the 360 mean that they may have been able to do a few things differently to help boost compatibility. It could be the AMD CPU is better at emulating a Power PC than the Power PC was at emulating the original's Intel CPU.

Looking at the initial list of games, it looks like a lot of Microsoft Studio games, with some smaller indie games that Microsoft Studio published on the 360. Are there any games on the list Microsoft didn't have a hand in? I'm guessing it's because they tested it out internally first, using only their own games to keep it quiet. Now that it's announced, I expect titles from other publishers to show up.

Jay G.

It would be cool if they made the "Games with Gold" titles a priority. Xbox One owners would potentially get 4 games a month they could play on their console.

chuckd21

The video Major Nelson posted make it looks like a virtual 360 running via your One.

https://twitter.com/majornelson/stat...88682173194240

RichC2

Which is what it should be, and frankly that's the only way to guarantee 100% on an emulator. Basically having the full 360 emulated as a virtual machine. Microsoft's virtual machine tech is pretty nice these days.

Jay G.

That has to be showing one of the development systems. I think they'll lock you out of most of the 360 UI, instead jumping you straight into the game.

I wonder if each game will have its own version of the 360 OS. I was thinking that'd add a lot of overhead, but the 360 OS is only 16MB disk space and 32MB RAM:
https://en.wikipedia.org/wiki/Xbox_360_system_software

RichC2

I imagine it'd be more like Wii mode on the Wii-U. With a single instance full 360 OS, but then again they may want you to pin all your downloaded software on your Xbox One mainboard, at which point that wouldn't work.

If you mess with the 360 OS in any way though, you risk messing up some of the titles, and what about patches and the like? It'd be tough to do that outside of a VM.

Mike86

I'm happy to hear about backwards compatibility coming to the One. There are a number of games I have yet to play for 360 and some that I'd like to replay. Granted at the moment I have both my 360 and One hooked up, but if I eventually get a PS4 I'll likely put the 360 in storage.

pinata242

All of that and my 360 is dog-shit-slow.

Jay G.

My understanding is that the "Wii mode" on the Wii-U isn't a VM, but more like the system rebooting onto the built-in Wii hardware and essentially running like a Wii, which means losing all the Wii-U features, like playing on the controller screen.

The Xbox One emulator looks more like it's running in a VM, and you're still able to access all the Xbox One features like screenshot, DVR mode, and broadcast.

Plus, they're limiting the games you can play, so they can't let you exit out to the main 360 Dashboard, where you'd expect you'd be able to download or run from disc any 360 game. Or maybe even using other 360 apps like for video or music.

Keeping each game in its own emulator VM would also help if it turns out a game needs a specific emulator tweak that could potentially break other games.

RichC2

You're right about the Wii mode on the Wii U, I just meant that'd it'd be a fully functional 360 running on an Xbox One much like the Wii on the Wii U. They can limit compatibility from within it, as anybody with a banned 360 can tell you, and it's still running on the One which will give it access to the newer features, like video sharing.

Something like a tap for the Xbox One menu, long hold for the Xbox 360 menu... or something.

If it's a properly developed VM, it wouldn't need tweaks for individual titles. As a standalone emulator it would, though.

I don't know, it's all speculation for now.

Jay G.

I don't get this. It has to do emulation, if only because the CPUs of the Xbox One and the 360 are completely different. So the theory is that it'll be an emulator, possibly running either a full or stripped down/restricted 360 OS, with the emulator being isolated inside a VM on the Xbox One.

A VM just isolates the hardware from other VM, with all the VMs designed to run on the same type of hardware. This is why Windows and Linux can run as VMs on the same server hardware, because they both support the same underlying hardware. Once the architecture is different, emulation is needed, and it's where compatibility issues can come up, since no emulator is perfect (no VM software is perfect either, but there's less issues to consider).

RichC2

Yeah I'm aware of that, emulation is emulation anyway you dish it. I've just seen more thorough processor/core emulation in a VM than I have through standalone program emulators.

Everything has issues though. Curious to see it work.

Jay G.

I'm not sure what you mean by "standalone program emulator" vs an emulator in a VM. Can you give an example?


Emulators are going to have to virtualize the underlying hardware. The degree of accuracy they do that depends a lot on the complexity of the hardware and how different it is from the hardware you want to run the emulator on. Sometimes, to go from say 97% accuracy to 99% accuracy takes a near exponential amount of additional computing power. See this article about the difficulty of completely accurately emulating SNES hardware on a PC:
http://arstechnica.com/gaming/2011/0...snes-emulator/

I'm thinking MS has a pretty accurate emulator for the 360 if they think that they're going to be able to easily emulate so many games. However, if the emulator is something like 99% accurate, but there's a glitch on one game, they may go with a game-specific fix instead of trying to improve the emulator's accuracy overall and lowering its overall performance.


Nintendo has basically been doing game-specific emulation for years with Virtual Console on the Wii and Wii-U. Each of those games gets a specially tweaked emulator to run that specific game, instead of trying to make the emulator for a specific system able to run every possible game.

Similarly, the PS3 software emulator for PS1 games is locked to only certain games. People have hacked it to play other PS1 games, but those not on the official compatibility list have issues.

RichC2

I got my terms backwards, it's monday, I'm sleepy. Obviously the architecture of the Xbox 360 and Xbox One are night and day different so virtualizing is out of the question, unless the Xbox One x86-64 CPU had an extended code set "just in case" which I'm going to seriously doubt.

What I was talking about was more getting the 360 OS running on a emulated version of the 360 processor using something like a QEMU version of the 360 processor without sharing resources with a host OS (minus the rather slender one that the Xbox One uses as its main GUI), but I honestly doubt that's even possible at this point in time since the emulated processor would have to be run on something. The interpretations on stuff like SNES emulators (and especially N64 emulators which are all sorts of fucked up) generally don't do even the 97% that gets reported. Or so I've been told. This shouldn't be an issue since Microsoft designed the Xbox 360 processor, but who knows.

That all said, at least the original Xbox should run fine on the Xbox One architecture

Jay G.

The Xbox One already has a hypervisor built in, and separates out hardware resources. The Xbox One UI runs in its own VM and utilizes at least one core to itself, while games have access to at least 6 cores. There's also a dividing out of the RAM, 3GB for the UI and 5GB for games.
http://microsoft-news.com/xbox-one-t...app-switching/
https://en.wikipedia.org/wiki/Xbox_One#Internals

So the "Game VM" in the Xbox already has dedicated resources that the emulator will be able to use.

RichC2

Hypervisor, that's the other term I was looking for. Jesus, I couldn't even think of the term Flower Bed a few hours ago and now this.

Music

Exactly!

Music

Hopefully they fix the Netflix app and the bug with it constantly going up, like if the controller was stuck... that crap just recently started for me.

Dan

Someone compiled a list of all the games shown in the backwards compatibility video. One would assume these are the games that are coming before the official launch.

Alan Wake
Assassin's Creed
Assassins Creed Brotherhood
Assassin's Creed: Revelations
Bayonetta
Bioshock
Bioshock Infinite
Borderlands
Brothers in Arms: Hell's Highway(?)
Call of Juarez
Call of Juarez: Bound in Blood(?)
Cars 2
Child of Eden
Civilization Revolution
Clash of Heroes HD
Dark Souls
Dark Souls 2
Dead Space
Fable 2
Fallout 3
Far Cry 2
Far Cry: Blood Dragon
Forza 2
Forza 4
Forza Horizon
Ghost Recon Advanced Warfighter
Ghost Recon Advanced Warfighter 2
Halo 3
Halo CE: Anniversary Edition
Halo Reach
Mass Effect
Ninja Gaiden 3
Pacman Championship Edition DX
Prince of Persia: The Forgotten Sands
Rainbow Six: Vegas
Rainbow Six: Vegas 2
Rayman Legends
Rayman Origins
Risen 3
Sacred 2
Saint's Row: The Third
Shadow Complex
Shadowrun
Sonic Adventure 2
Soul Caliber V
Splinter Cell: Double Agent
Toy Story 3
Vanquish

Jay G.

Here's a summary of the press conference:
https://news.microsoft.com/2015/06/1...-xbox-history/


Also announced: Rare Replay, a 30-game compilation of Rare games for $30:
http://www.ign.com/articles/2015/06/...d-for-xbox-one