Monday, November 24, 2008

Convey's Reconfigurable Computing System in the NY Times

An article in the New York Times discusses Steve Wallach's Convey Computer Corporation and their new reconfigurable supercomputer.

The Convey machines use FPGAs to augment the CPU's instruction set. From a given FORTRAN or C code, their compiler tools create a "personality," which is Convey's way of re-branding the term "configuration."

Steve has a great quote on his site, which sums up everything I've ever written about the FPGA market on this blog: "The architecture which is simpler to program will win." I was once an intern at Xilinx pushing FORTRAN code through F2C (which redefines "barf" in the f2c.h header file) and massaging the resulting C code through an FPGA compiler. As a general rule, most important milestones in compiler technology diminish the need for a summer intern's manual labor. But while I understand the importance and value of demonstrating the capability of reconfigurable supercomputing on legacy FORTRAN applications, if FPGA supercomputing has a future, I am convinced that we need to break free of the instruction stream control flow model.

I've previously argued that the any approach to accelerating sequential imperative languages like C and FORTRAN only extends the von Neumann syndrome and that we need an explicitly parallel, locality-constrained, dataflow model akin to the spreadsheet if we hope to create scalable applications. Moore's law continues to drive down the cost of a transistor, but the speed of these transistors is limited by a power wall; if we are going to continue the geometric cost reduction of Gigaops, then we need languages and programming models that improve with more transistors and not just with faster transistors.

I agree with Ken Iverson's thesis in "Notation as a Tool of Thought." The Sapir-Whorf Hypothesis holds true in computer languages: we are bound to the von Neumann model by the languages we know and use and this is what we must change. In many of his talks and papers, Reiner Hartenstein identifies the dichotomy between von Neumann and reconfigurable computing paradigms. He argues that the divide must be overcome with an updated computer science curriculum.

Programming models aside, the main thing bugging me about the Convey machine is it's price tag: $32,000. Here's what Joe at Scalability has to say about pricing FPGA acceleration reasonably:
One company [at SC08] seemed to have a clue on the FPGA side, basically the pricing for the boards with FPGAs were reasonable. Understand that I found this surprising. The economics of FPGA accelerators have been badly skewed … which IMO served to exclude FPGAs from serious considerations for many users. With the rise in GPU usage for computing, some of the FPGA folks finally started to grasp that you can’t charge 10x node price for 10x single core performance.
I really hope that Convey's increased programmability helps them make huge inroads at this price point so that we can expect super high margins from our products when we launch. I don't know how they will compete with XtremeData, DRC, Nallatech, Celoxica or whoever decides to do the same thing all these companies do with Achronix chips (hmmm...)

Tuesday, November 11, 2008

Software Defined Radio: Revolution Not Included

Spectrum policy needs to be re-evaluated in the 21st century. The expansion of the Internet as an organizational model destroys one-way, hierarchically controlled mediums. A Wired article earlier this year observed that the nature of the Internet is to make everything it touches tend to gratis. The Internet and the wireless world are now inextricably linked by devices that support both free protocols on free spectrum and proprietary protocols on licensed spectrum. VoIP-capable WiFi-enabled phones are the beginning of the end of cell-phone service as we know. Regulated spectrum ownership will transition to universal Ethernet coverage using best effort spectrum sharing protocols.

With the move to digital TV the bandwidth requirements for television broadcasting decreases substantially, freeing up a large amount of white space bandwidth between existing channels. A programmable transceiver can operate on these white spaces switching between multiple protocols to serve other white space devices. If we make a transceiver device that can access this huge amount of bandwidth, we can build a substantial, free wireless network.

Google's Larry Page spearheaded the Free the Airwaves campaign which urged the FCC to free these white spaces for unlicensed public use. On election day, the FCC unanimously voted in accordance with these wishes, approving devices that use sensing and geographical information to avoid interference. The white spaces are the first frontier. We should promote a long term vision that would have the FCC open the entire spectrum to sharing protocols. TV and Radio broadcasting are an enormous waste of bandwidth and discriminatory allocation of bandwidth is one of the pillars of inequity in modern American society (think nationally syndicated talk radio). The roadmap for the obsolescence of spectrum ownership should be set so that capital can be allocated properly to progressive technologies. Unfortunately this technology direction is contrary to the current revenue model of the FCC and would likely result in the re-purposing of that organization.

The economic challenge in making this transition is that there are hundreds of billions of wealth units tied to the premise that spectrum can be owned. I expect to see the wireless and media empires crash as the premise of their business model is made unsound by technical obsolescence. The question is: where does all this money go? The answer is nowhere: it just disappears. This effect is similar in substance and larger in magnitude to the hundreds of millions of dollars of market value in newspaper classifieds that disappeared because of Craigslist.

The technical possibility for multi-band and spread spectrum sharing owes itself to the widespread availability of wired Internet infrastucture and the rapid buildup of digital signal processing technology driven by the geometric decrease in transistor cost. Software Defined Radio (SDR) devices like the GNU Radio USRP (FPGA-inside) can be programmed to operate in arbitrary frequency ranges with arbitrary protocols. As more spectrum becomes freed, SDR devices can be reprogrammed in the field to use these new ranges.

This democratization of signal processing technology and communications infrastructure also fueled the cost reduction of music production and distribution that made the recording industry obsolete. Without the teeth of copyright law, and without a monopoly on the electromagnetic spectrum, the decline of the telecoms will be more rapid than the RIAA, and hopefully without the resentment generated by lawsuits against customers.

We have previously seen the effect of technical obsolescence on existing markets and we know the response from the tech that was superseded: the destruction of wealth is often met with lawsuits. Organizations like the RIAA claim that they protect the interests of artists and the industry surrounding them by transforming antiquated copyright laws into censorship laws for the "digital millenium." Unlike the recording industry, there will be less legal claws gripping onto a futile business plan during the technical obsolescence of the telecom industry.

Spectral freedom ultimately favors device manufacturers and consumers to the chagrin of telecoms carriers, content owners and distributors (aka "the middle men"). I think the winning business model will beat Apple to the white-space iPhone/laptop, open its API, and have a good tranceiving router to back it up. Initially, software controlled protocols and devices that take advantage of them will be patented and will be valuable to carriers who want to lock-in their customers. These proprietary technologies will eventually be replaced by open source alternatives. I expect there will be some legal antagonism between proprietary device manufacturers and the free culture communities, but the futility of protocol licensing is the same as spectrum ownership. Software Defined Radio is software after all, and each FPGA configuration is just a very large number. Be skeptical of the business plan of people who troll electronic bridges for large numbers. Proponents of protocol licensing will point to the number of jobs lost, and appeal to the false-utopia of full-employment using some form of the broken window fallacy (sure the spectrum ownership and patent protection policies are broken, but look at how many people they employ!).

Companies like Motorola and Nokia can use the white-spaces to attract customers to products that are compatible with "WiFi 2.0," as Google likes to call it. They should start to charge the actual price of their equipment so they can become free of their dependency on the carriers. Sprint, Verizon and AT&T should milk those SMS fees while they still can: freedom in the white-spaces will annihilate their industry. The writing is on the wall.