Xbox One Architecture Panel *Main Console HW Points* Transcript

[blakjedi]

They kept talking "supercomputer" design. It will be interesting to see where this goes.

 

[3dcgi]

They might be talking about a cluster of Palladium boxes.

 

[BeyondTed]

They might be talking about a cluster of Palladium boxes.

Thanks, interesting reading. Seems to be processor based.

From that I found: (FPGA based?)

http://www.cadence.com/products/sd/rapid_prototyping/pages/default.aspx

http://www.deepchip.com/items/0517-06.html

http://www.cadence.com/products/sd/palladium_xp/Pages/default.aspx

Older PDF than Palladium III (2010 for XP PDF, 2011 for Palladium III PDF) but seems to be newer version.



Hope someone out there can comment more as this seems to suggest MS was doing serious custom work.

 

[dirtyvu]

there's a fully transcribed video on Youtube of the presentation:

https://www.youtube.com/watch?v=vg_DR0leAYw

 

[Tchock]

Re: flash cache vs hybrid HDDs...
Desktop operating systems are never fully aware of, or adapted to use flash. That's why hybrid HDDs or even Intel's Smart Response take a bit more of a hackier approach (MFT lookups?).

Otherwise 8GB is a lot in specificity: you could hold tens of tombstoned apps (or 2-3 games in tombstoned state) that are ready to switch over at any moment. I suspect this has been absent in devkits and also the first display units, popped up later as a remedy (remember the really choppy Live TV interface, allegedly filmed in April?)

 

[Dominik D]

if this is what he's talking about, what would be the positives of it in game development?

The points from the panel are pretty vague, but there are interesting tidbits thrown in. I'd love to know more.

Good hard drives have had this kind of stuff built in for quite some time now. It's a matter of size and where is it really (is it part of the HDD or separate, to changing drive doesn't replace the cache). If it's closer to the RAM than HDD then it's an interesting case. Otherwise it's just a glorified HDD. What's interesting about these things is how you use it for writable data and how you deal with power outage. It's also important whether OS (and in extension: developer) has any say in what/how/when/where is cached. Caching in modern HDDs tends to be pretty smart but this could interact poorly with how OS tries to be smart about IO.

In the sense of HDD caching? I can't think of any circumstance where that would be useful for a game in a next-gen console.

It'd be massive for audio data, probably. Audio tends to be huge. There's Bungie's presentation on their approach to streaming audio and how they scale down stuff like chatter and on-off audio files because access to the HDD is too slow.

 

[Rangers]

Re: flash cache vs hybrid HDDs...
Desktop operating systems are never fully aware of, or adapted to use flash. That's why hybrid HDDs or even Intel's Smart Response take a bit more of a hackier approach (MFT lookups?).

Otherwise 8GB is a lot in specificity: you could hold tens of tombstoned apps (or 2-3 games in tombstoned state) that are ready to switch over at any moment. I suspect this has been absent in devkits and also the first display units, popped up later as a remedy (remember the really choppy Live TV interface, allegedly filmed in April?)

I hope it can help games too. Not much has been spoken about it.

 

[Betanumerical]

I hope it can help games too. Not much has been spoken about it.

From what we know itll be somewhere between 53-200MB/s of bandwidth. Thats about all we know about it for now to be honest.

 

[-tkf-]

"We added lot's of memory both system memory and flash cache in order to have that simultaneous and instantaneous action."

First time hearing about the flash cache how much flash cache are they talking about or is this just the esRam?

Isn't that the 8GB that was revealed at Hotchips?

 

[warb]

I hope it can help games too. Not much has been spoken about it.

It should be used to boost loading for games and apps, otherwise what?

 

[Rangers]

Some gaffers were thinking it might just be only to store the OS or something. Not games "or they'd have talked about it".

 

[Jwm]

Why not use it for tombstone? Well unless it is always on, then I guess it would not need to dump the ram. So I guess it could be for the OS, or for reinstall files (which would be a waste of the speed).

 

[Shifty Geezer]

Use for the OS means zero write concerns. The OS will rarely be written to, and it'll also be more responsive. The only other option for the OS is to include it on HDD which'll be slower loading, although if the intention is to never switch the console off, longer boot times won't be as much of an issue. 8 GBs is also a lot for OS, so maybe something like 4 GBs OS, 2 GBs for file IO, and 2 GBs free to help with wear and tear.

PS3's OS was on flash, as is Wii Us, and every smart device out there. It's a sensible choice.

 

[Cyan]

Use for the OS means zero write concerns. The OS will rarely be written to, and it'll also be more responsive. The only other option for the OS is to include it on HDD which'll be slower loading, although if the intention is to never switch the console off, longer boot times won't be as much of an issue. 8 GBs is also a lot for OS, so maybe something like 4 GBs OS, 2 GBs for file IO, and 2 GBs free to help with wear and tear.

PS3's OS was on flash, as is Wii Us, and every smart device out there. It's a sensible choice.

By wear and tear..., do you mean using it as a cache in games? I haven't seen it mentioned here often recently but wouldn't the additional cache help under stress situations where you need to load some data fast in games which require it, i.e. sandboxes?

I think the additional flash will certainly help to remove popping in games all together, most people are unsympathetic to it.

 

[Shifty Geezer]

By wear and tear..., do you mean using it as a cache in games?

Yes, and write fatigue leading to flash failure. That's been one of the issues debated over the viability of flash long-term as a storage in consoles (I recall suggestions of its use for video caching and whether it'd get burnt out or not). Constant writing to flash will damage it eventually. How much so is an ongoing debate, but you know that for use for OS where it's only written to for updates (about once a week in the case of PS3 ), there are no such concerns. The moment you start caching game data and frequently overwriting that, you have issues with write fatigue which, on a chip soldered to the mobo, is adding to total system failure probabilities. If on year three, every console starts to die because the flash has been burnt out, you'd have an awful lot of repair expense to worry about!

 

[warb]

Some gaffers were thinking it might just be only to store the OS or something. Not games "or they'd have talked about it".

That'd be a big old OS. It seems more likely that it's there for everything, like a hybrid drive. Games are getting bigger and the HDD won't be so quick on its own.

How do tablets and ultra books deal write fatigue?

 

[Shifty Geezer]

How do tablets and ultra books deal write fatigue?

They get replaced long before it ever becomes an issue!

You also load directly from the flash, rather than writing to it as a flash cache would be subjected to in a console. It doesn't endure a tiny fraction of the write wear of an HDD cache.

 

[dobwal]

http://www.networkworld.com/news/2011/021711-microsoft-flashstore.html
http://research.microsoft.com/en-us/news/features/flashstore-021411.aspx

First, FlashStore introduces flash as a cache in the memory hierarchy between RAM and hard disk so that the flash memory holds a “working set” of data—information a computer is most apt to need. FlashStore tracks data use so that, as data becomes less frequently accessed, it eventually is sent back to the hard drive so that new, fresh data can take its place. That makes better use of flash while still getting much faster retrievals than are possible with a hard drive.

Second, FlashStore is designed to eliminate random writes. It organizes data in a log structure on flash so that new data sent to flash does not lead to random writes and, hence, is not subject to garbage collection by the device. FlashStore aggregates small writes from the application into a write buffer in memory and writes to flash when there is enough data to fill a flash page. By making writes sequential to flash, FlashStore makes much better use of flash-device architecture. If the application needs strict data-durability guarantees, FlashStore can aggregate writes in memory up to a timeout interval provided by the application or when a flash page worth of data is amassed, whichever comes first.

Finally, FlashStore is designed to use RAM efficiently by employing a specialized RAM index to access the data on flash. It uses a hash-table-based index in RAM that is designed to save space along both the vertical and horizontal dimensions—the number of slots and the size of each slot, respectively.

Xbox Live servers uses Flash Store already and is used to speed up online gaming.

 

[Rangers]

Yes, and write fatigue leading to flash failure. That's been one of the issues debated over the viability of flash long-term as a storage in consoles (I recall suggestions of its use for video caching and whether it'd get burnt out or not). Constant writing to flash will damage it eventually. How much so is an ongoing debate, but you know that for use for OS where it's only written to for updates (about once a week in the case of PS3 ), there are no such concerns. The moment you start caching game data and frequently overwriting that, you have issues with write fatigue which, on a chip soldered to the mobo, is adding to total system failure probabilities. If on year three, every console starts to die because the flash has been burnt out, you'd have an awful lot of repair expense to worry about!

For that they would probably include hefty amounts of overprovisioned redundant flash, just like consumer drives do. "8GB" flash might be 16GB with 8GB accessible.

I'm going to assume if it's to be used for games they know it's going to last.

Wearing out would be a big concern though I guess because unlike the HDD you cant just pop another one in.

But then again we already have 4GB 360 and 12GB PS3 based on flash.

 

[Shifty Geezer]

But then again we already have 4GB 360 and 12GB PS3 based on flash.

Like the smart devices, this is mostly as read-only storage, unlike an HDD cache that's constantly having its data replaced (depending on how much that happens).