Apple's A6 Details and Timeline Emerge 123
MojoKid writes "For a CPU that hasn't seen the light of day, there's a great deal of debate surrounding Apple's A6 and the suggestion that it may not appear until later in 2012. The A6 is a complex bit of hardware. Rumors indicate that the chip is a quad-core Cortex-A9 CPU built on 28nm at TSMC and utilizing 3D fabrication technology. While the Cortex-A9 is a proven design, Apple's A6 will be one of the first 28nm chips on the market. The chip will serve as a test case for TSMC's introduction of both 28nm gate-last technology and 3D chip stacking. This is actually TSMC's first effort with an Apple device. The A4 and A5 have both historically been manufactured by Samsung."
Re:Unbelievable (Score:2, Informative)
Not sure if this post was intended to be serious, but we're not talking about stacking them to a particularly large height. A single wafer is far thinner than any practical phone thickness, and a few of them stacked is still super-thin.
Re:Quad Core In a Tablet/Phone? (Score:5, Informative)
Dual core CPUs allow the OS to do one thing in the background and not bog down the device for the running application, but what on earth are you going to do with 4 CPUs when you can only interact with 1 program at a time?
You do know that iPhone apps can do quite a lot in the background, even if only one app can have focus at one time, right? Right now apps are deliberately curtailed to only certain background activities because of the limitations of the amount of cores, adding in more cores and more powerful cores will allow apps to do more in the background.
The limitation of being able to interact with one app at a time is due to UI constraints. Even on a regular computer there isn't much case for multiple programs being visible to the user at one time. For the most part a user isn't able to fully interact with multiple programs at a time, the usual case is to view a document in one app while doing work in another. A better solution to this is to allow programs to share their display engines so that a single program can run and display documents from other programs while only having one program running at a time.
The model of one application running with a few lighter weight processes doing background work makes sense for devices with tight resources and that's the model that iOS is attempting to follow.
Re:Quad Core In a Tablet/Phone? (Score:4, Informative)
That is assuming that Apple actually put multithreading into their iphone SDK.
Of course there's threading [apple.com] in iOS. There are examples [xprogress.com] to be found if you google for them.
Re:Stacked Chips (Score:5, Informative)
They lost a court case in the UK over this a couple of years back - for strange historical reasons, you pay VAT on crisps, but not on cakes.
The strange historical reasons being that some bright spark thought they could be really clever by only charging VAT on "non-essential" items, thus creating endless work for lawyers and committees arguing over what was "essential".
...and as anybody who watches QI knows, the official definition is that "cakes" go hard when they are stale [wikipedia.org], whereas biscuits* go soft.
* That's biscuits as in British English, i.e. cookies or crackers - not scones (which I guess are cakes).
Re:Quad Core In a Tablet/Phone? (Score:0, Informative)
You should report for Fox News. I get all of my tech and science news there. I hear they are looking for fact based news that is fair and balanced...
Re:Quad Core In a Tablet/Phone? (Score:4, Informative)
The article is talking about things long in the past, I have a HD5850 in my machine that's almost two years old and built on 40 nm process from TMSC. That process has been fairly stable for a long time now even though it was a bit delayed and early yields weren't as good as hoped. Where they have really struggled is with their 32-34 nm - I don't remember exactly - process that should have gone into the last generation of chips. In short, they ended up simply skipping it since they were due to deliver 28 nm by the time it would be ready. And there's actually three 28 nm processes, LP, HPL and HP which you can call low, mid and high-power. LP is really just for support chips, but it's rumored that HPL will be used for the next generation Cortex and AMDs Southern Islands, while nVidia is waiting on the HP process for their next generation. For the GPU business it just means progress is slower - both AMD and nVidia are stuck waiting for TMSC. For CPUs on the other hand Intel and GlobalFoundries are heavy competitors - GF to take over the business while Intel only produce for themselves - but being a process step behind is like fighting with one hand tied behind your back.
Re:What is a 3D stacked chip for a fab? (Score:4, Informative)
From 3D stacked chip, I'm assuming that they'll be stacking multiple die on each other, like in an MCP.
Stacked chips having been happening a long time. The A4 and A5 are stacked with the CPU and the memory on top of each other. Technically there is no reason why they can't stacked CPUs on top of each other. Practically, I suspect heat is a problem.
The other part of the question - iOS - is it something that's as SMP enabled as OS-X is? From what I've seen of i-PADs, they are not multi-tasking OS's at all - all they do is save the state of an app once you exit it, and resume from that point if you return. If that's the case, how does multiple cores help for this case?
iOS is based on OS X which is based on BSD so yes SMP is there. Your knowledge about iPads is very out of date. The hardware itself is capable of multitasking as you play music while surfing web. The APIs that Apple exposes limits how applications access the multitasking. Fast-switching is the most common used version because most applications don't really need to keep running while not being used. However Apple provides seven different multitasking models [wikipedia.org] in iOS 4 released more than a year ago.
Finally, Apple can make this chip even better for themselves by moving their macs and airbooks to this processor, so that they have just one CPU platform of their own, making it easier to have a common code base for their apps, like Safari, Mail, et al.
Except that ARM and x86 instruction sets are not compatible. You can emulate x86 in an ARM environment but it will be painfully slow. Emulating ARM in an x86 environment will work but there's no real point other than coding and debugging for something like iOS.