A 2007 IDC study estimates that the world generated 161 billion gigabytes of digital information, and that the pace of increase in the information we deal with will outstrip our capacity to store it by 2010 (see insideHPC post). All this data -- conversations, television programs, music, movies, stock trades, commodities values, medical images, shopping lists, and test results -- isn't just a statistical artifact. It is the stuff that drives the scientific, economic, and social engines of our society.

I spoke with Nagui Halim, director of event and streaming systems at IBM Research, about IBM's stream computing efforts and where he sees the field going. He framed the problem for me by pointing out the fundamental difference between the computing that most of us do every day, and stream computing: "In traditional computing the machine dictates the pace at which things gets done. In stream computing, the machine's job is to figure out what's going on in the real world in real time."

This sounds fairly innocuous, but when you try to put this principle into practice, the challenges start to add up. For example, according to Halim the financial services industry generates five million data items per second. One way to make money in the markets is by exploiting information asymmetries, that is, cases where you know something that most people don't. In some situations these asymmetries only exist for a few seconds. So real-time systems supporting these applications have to be able to consume, analyze, and react to the millions of pieces of data they are seeing in a just few milliseconds, and then move on to the next 5 millions pieces of information. The same kinds of demands exist in real-time monitoring of complex industrial processes such as chip manufacturing, credit card fraud detection, commercial flight tracking, and so on.

Of course these data streams didn't spring up overnight, and companies have experience building solutions to handle all of this information. The efforts to date have all been focused on solving specific problems in specific businesses. Halim's goal is to take what's been learned from the various point solutions that industry has developed to deal with information flows as they happen, and build a generalized infrastructure and body of knowledge that will accelerate the adoption of stream computing by researchers and individuals alike. Halim and IBM are working the whole solution, from hardware, operating systems, and compilers to middleware and tools.

Although this is still a project in IBM's labs, the existing stream computing software base includes millions of lines of code and over 300 patents. Many books and papers have been written about the work they are doing. Now, the stream environment that IBM has built is being tested in the real world. One of those pilots, with TD Bank Financial Group in Canada, is using a Blue Gene and IBM's stream computing software to support trading operations (see IBM's press release from April).

IBM is relying on its stable of HPC hardware to provide the computational horsepower needed to support large scale stream computing, but not in the way you might expect. "The general model for HPC is to take a large problem and split it up into pieces. In stream computing we're organizing the computation in quite a different way," says Halim.

According to him, many stream computing applications can be organized as a pipeline, subdividing supercomputers into pools of processors that each deal with the needs of a specific stage of the pipeline, taking the data that comes in and transforming it for further action in a subsequent stage. For example, in a voice processing application, the stages might be organized to first decrypt individual voice packets, assemble packets into a conversation, convert the conversation to text, and then analyze the text looking for key phrases of interest that might alert a human or spark additional action and analyses. Depending upon the amount of voice information coming in, you might need 10s, 100s, or 1,000s of processors to handle the load.

But where Halim's team is really focused is on the software infrastructure needed to address stream computing needs in a universal way. The goal is to provide a general-purpose model of creating a stream application from individual data processing components that can be assembled to produce the desired results. The stream environment needs to be able to adapt to the information it is seeing, allowing it to focus on areas of interest and rapidly move past uninteresting features or trends. The environment also must be able to adapt when the user's needs change, and react to changes in the resources (both human and computer) available to work on the problem.

Importantly, IBM is designing the stream infrastructure to be useful to non-experts from the ground up, which would be a welcome change from much of the software that is written for supercomputers.

One facet of this strategy is that the environment can run applications on resources varying from laptops to supercomputers, automatically taking advantage of the computational attributes of the hardware available to it, and with the ability to schedule tasks around hardware failures. The stream software environment also includes composable generic components (e.g., join operators, dominant contributor in an array, change point detection, and so on) that will make the system useful right out of the box, allowing non-experts to do useful work with a short learning curve.

And out of the box it will come. Although this is still a research project and there remains much work to be done before the product is shrink wrapped, Halim and his team are motivated by an expansive view that "stream computing is not just a new computing model, it is a new scientific instrument."