Monday, 23 September 2013

Balanced, but fair?

So i've been following the xbone trainwreck over the last few months. It's been pretty entertaining, I like to see a company like m$ get their comeuppance. It's been a complete PR disaster, from the meaningless "180" to the technical specifications.

The FUD is stinking up the discourse a little though so here's a bit of fudbusting of my own.


Balance is an interesting term - but only if you've fucked up somewhere. Every system aims to be balanced within it's externally determined contraints - that's pretty much the whole point of systems engineering. It relates to the efficiency of a given design but says NOTHING WHATSOEVER about it's performance.

One of the main constraints is always cost and clearly that was one of the major factors in the xbone cpu design. Within the constraints of making a cheap machine it may well be balanced but it's certainly not as fast as the current competition.

m$ are trying to use the chief ps4 engineer's words against him in that he stated that they have more CU's than is strictly necessary for graphics - but the design is clearly intented to use the CU's for compute from the start. And in that scenario the xbone's gpu becomes unbalanced as it has inadequate ALU.

For the sort of developer that works on games I imagine GPU coding is really pretty easy. And with the capabilities of the new HSA-capable devices it should be efficient too - as soon as one has any sort of parallel job just chuck that routine on a GPU core instead of the cpu. Not catering for this seems short-sighted at best.

"Move engines"

These are just plain old DMA engines. Every decent personal computer has them since the Amiga 1000. They have them because they are useful but there's nothing particularly special or unique about them today and the AMD SOC in both consoles will have these - infact they will have several.

Even the beagleboard has a few of them (i can't remember if it's 2 or 4), and they can do rectangle copies, colour fill and even chroma-key. The CELL BE in the PS3 has a 16-deep DMA queue on each SPU - allowing up to 16 in-flight DMA operations PER SPU (i.e. 112 per CELL BE, not including other DMA engines). The epiphany core has 2 2-D DMA channels per EPU - or 32 independent channels for a 16-core chip.

They don't take too much hardware to implement either, just a couple of address registers, adders and a memory interface/arbiter (the biggest bit).

Hardware Scaler & "Display Planes"

i.e. overlays. Video hardware has had this sort of functionality for a couple of decades. IIRC even the lowly beagleboard has 3 "display planes" one of which has an alpha channel, and two of which can be scaled independently using high quality multi-tap filters and two of which support YUV input. Basically they're used for a mouse pointer and a video window, but they could be used for more.

Overlays are really useful if you have a low-bandwidth/low-performance system because of the "free" scaling and yuv conversion, but aren't going to make much of a difference on a machine like the xbone. For example even at 68GB/s one can read or write over 8000x1080P 32-bit frames per second, so you're looking at only a few percent maximum render time on a 50fps display for blending and scaling several separate display planes.

Good to have - sure, but no game-changer and certainly no unique 'value add'.

DRM & the 180

Personally I don't think anything much changed with their "180" on the DRM thing. DRM is still there, and even without a nightly parole check there are plenty of ways to have effectively the same thing. e.g. make a game pretty shit without being constantly on-line, tie a given disk to an account the first time you use it, and so on. And whatever they were planning could always be turned on at the flick of a switch at any future point in time (it needn't have to work with any game previously published, just with ones published after that point).

BTW Sony are really no better here despite all the free PR they wallowed in. Sure they never tried the really dumb idea of banning second hand sales of physical discs (it was an absurd idea anyway as much of they money you might make back from it would be swallowed in adminstration costs and given it would kill the used game market it would probably just end up being revenue negative). But they're making download-only attractive enough that people are foregoing their rights for convenience and the end result is pretty much the same.

All consoles have always been heavily laden with DRM - it was always one of their selling points to developers to negate the wide-spread sharing that everyone does on personal computers.

I can't see the difference...

This is just straight-up PR speak for "we don't expect the average (i.e. uneducateD) `consumer' to notice the difference".

Would you like some condescention with that?

It's all FUD and Games

The great thing about FUD is you don't even have to do much. Say a couple of things in the right places and you get ill-informed but well-intentioned people doing all your work for you. They don't even realise they've been manipulated.

We'd all let the games speak for themselves if we could actually see them ... but developers have to sign NDAs that wont let them talk about the differences, and rumours suggest they're not even allowed to show the games side-by-side at trade shows. So telling people to "see the games" is being very dishonest at best. It's just a FUD teqnique to try to get people locked in to buying their product. Once they get it home and see they've been sold a lemon few will be motivated to do anything about it, and if they get enough early adopters the network effects take over (this is why they're scambling so much even though they were clearly aiming for a 2014 launch - it has to be now or never, at least in their grand plan).

From what we can see the xbone was basically created as the end-game for their trojan horse in the home idea - a $700 hand-wavey remote control that you have to pay a subscription to use, and which monitors demographics and viewer reactions and serves advertisements appropriately. Playing games is only a secondary function - as can clearly be seen by the technical specifications.

If playing games was the primary function of the design then they simply "done fucked up". A company this big doesn't waste this much money over the course of a decade to fuck up at the end of it.

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