We are fast approaching the point where cell phone sized devices will have sufficient processing power to perform functions traditionally executed by a personal computer. There is some question as to whether this is necessary or desirable. With access to the internet, the processing can be performed by machines on the network. This goes back to the conflict between centralized processing versus decentralized. Centralized processing is desirable when the cost of processing power is high. In this particular case, the expectation would be that the cost of processing power is lower in a server form factor than a cell phone. There are costs associated with this solution with respect to the decentralized solution. First, reliability is lower because the reliability of the network affects all processing tasks. Second, network traffic is increased because communication must take place for all processing tasks as well as other communication. Third, privacy is compromised due to the extent that personal information is stored on a server that is likely not in control of the user and is transferred frequently between the mobile device and server. For these three reasons, it is very desirable to have decentralized processing. Therefore, it will be desirable to have hand-held computing.
Given that hand-held computing will happen with it just being a matter of when, there is still the question of what will become the dominant platform. Intel and AMD are reducing the power consumption of their x86 based microprocessors and platforms while ARM based smart phones are becoming more powerful every year. On the software side, it will likely be Windows and Linux versus Nokia’s open source Symbian. Apple seems flexible enough to operate on either x86 or ARM, as they are currently doing so with Mac and the iPhone, though their software development is much more extensive on x86. Presuming that processing will migrate into mobile devices and will not become centralized, compatibility will remain important. This will lead to a natural advantage for x86 as functionality on cell phones comes to resemble regular computing.
There is also a question of performance. The challenge for x86 is to reduce power consumption down to a scale appropriate to a cell phone sized device. For ARM, the challenge is to scale up the capabilities of the architecture for general purpose computing. Intel has made it half-way by scaling their processor power consumption down to 0.5W while achieving the ability to run Windows XP with Atom. This is low enough power consumption to be a viable smart phone chip. The holdup is with the rest of the platform, which has been rather disappointing. Intel has failed to sufficiently reduce the size and power consumption of the chipset, Poulsbo. This could take a couple more revisions to iron out, a fact which may have motivated Apple to look for an alternative, possibly prompting the acquisition of P.A. Semi. It seems likely that the plan is to develop a high performance cell phone platform in either the Power or ARM architecture. It isn’t evident which, since P. A. Semi is rumored to be discontinuing support of their PWRficient processors based on the Power architecture. This implies that they are going in a different direction, possibly scaling ARM up instead of scaling Power down to meet cell phone sized computing needs. Needless to say, it shall be interesting to see what develops as there is considerable microprocessor design talent at P.A. Semi.