ing community as they saw how the more rapidly evolving CMOS micro would overtake bipolar-based minicomputers, mainframes, and supercomputers if they could be harnessed to operate as a single system and operate on a single program or workload.

In the Innovator’s Dilemma, Christensen describes the death aspect basis of Bell’s Law by contrasting two kinds of technologies [ 4]. Sustaining technology provides increasing performance, enabling improved products at the same price as previous models using slowly evolving technology; disruptive, rapidly evolving technology provides lower-priced products that are non-competitive with higher-priced sustaining class to create a unique market space. Over time, the performance of lesser-performing, faster-evolving products eventually overtakes the established, slowly evolving classes served by sustaining technology.

From the mid-1980s until 2000, over 40 companies were established and went out of business attempting to exploit the rapidly evolving CMOS microprocessors by interconnecting them in various ways. Cray, HP, IBM, SGI, and Sun Microsystems remain in 2008 to exploit massive parallelism through running a single program on a large number of computing nodes.

Two potentially disruptive technologies for new classes include:

• The evolving SFF devices such as cell phones are likely to have the greatest impact on personal computing, effectively creating a class. For perhaps most of the four billion non-PC users, a SFF device becomes their personal computer and communicator, wallet, or map, since the most common and often only use of PCs is for email and Web browsing—both stateless applications.

• The One Laptop Per Child project aimed at a $100 PC (actual cost $188 circa November 2007) is possibly disruptive as a “minimal” PC platform with just a factor-of-two cost reduction. This is achieved by substituting 1G of flash memory for rotating-disk-based storage, having a reduced screen size, a small main memory, and built-in mesh networking to reduce infrastructure cost, relying on the Internet for storage. An initial selling price of $188 for the OLPC XO- 1 model—approximately half the price of the least-expensive PCs in 2008—is characteristic of a new sub-class. OLPC will be an interesting development since Microsoft’s Vista requires almost an order of magnitude more system resources.

FUTURE CHALLENGES
The Challenge of Constant Price, 10– 100 billion
Transistors per Chip, for General-Purpose Com-
puting. The future is not at all clear how such large,

leading-edge chips will be used in general-purpose computers. The resilient and creative supercomputing and large-scale service center communities will exploit the largest multiple-core, multithreaded chips. There seems to be no upper bound these systems can utilize. However, without high-volume manufacturing, the virtuous cycle is stopped—in order to get the cost and benefit for clusters, a high-volume personal computer market must drive demand to reduce cost. In 2007, the degree of parallelism for personal computing in current desktop systems such as Linux and Vista is nil, which either indicates the impossibility of the task or the inadequacy of our creativity.

Several approaches for very large transistor count (approximately 10 billion transistor chips) could be:

• System with primary memory on a chip for reduced substantially lower-priced systems and greater demands;

• Graphics processing, currently handled by specialized chips, is perhaps the only well-defined application that is clearly able to exploit or absorb unlimited parallelism in a scalable fashion for the most expensive PCs (such as for gaming and graphical design);

• Multiple-core and multithreaded processor evolution for large systems;

• FPGAs that are programmed using inherently parallel hardware design languages like parallel C or Verilog that could provide universality that we have not previously seen; and

• Interconnected computers treated as software objects, requiring new application architectures.

Independent of how the chips are programmed, the biggest question is whether the high-volume PC market can exploit anything other than the first path in the preceding list. Consider the Carver Mead 11- year rule—the time from discovery and demonstration until use. Perhaps the introduction of a few transactional memory systems has started the clock using a programming methodology that claims to be more easily understood. A simpler methodology that can yield reliable designs by more programmers is essential in order to utilize these multiprocessor chips.

Will SFF Devices Impact Personal Computing? Users are likely to switch classes when the performance and functionality of a lesser-priced class is able to satisfy their needs and still increase functionality. Since the majority of PC use is for communication and Web access, evolving a SFF device as a single communicator for voice, email, and Web access is quite natural. Two things will happen to accelerate the development of the class: people who have never