FYI,

DW

-------- Original Message -------- Subject: [QueueNews] A Conversation with Steve Ross-Talbot From: QueueNews <queu...@acmqueue.com> Date: Mon, March 13, 2006 11:00 am To: queu...@acmqueue.com

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ . . . . . . . . . . . . . . . . . . . . . . . . Queue E-Mail Newsletter for the Week of Mar/13/2006 . . . . . . . . . . . . . . . . . . . . . . . . ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ------------------------------------------------- Sponsored by

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Latest Articles:

A Conversation with Steve Ross-Talbot Ever heard of the pi-calculus? This man thinks it can revolutionize BPM. http://acmqueue.com/rd.php?c.370 (scroll down to read an excerpt from this article)

Going with the Flow Workflow systems can provide value beyond automating business processes. http://acmqueue.com/rd.php?c.369

Latest Blog Posts:

Charlene O'Hanlon

Coming Around Full Circle http://www.acmqueue.com/modules.php?name=News&file=article&sid=363 At the risk of disclosing my age, I confess I was struck with a tinge of nostalgia last week upon hearing the news of AT&T's plans to buy out BellSouth. Yes, it seems everything old is new again.

RFID Realities http://www.acmqueue.com/modules.php?name=News&file=article&sid=358 So here we are, three years after big box retailer Wal-Mart jump-started the RFID phenomenon by mandating all its suppliers incorporate RFID tags on their cases and pallets. Most of you know the story already: Wal-Mart said that by forcing its suppliers to supply the RFID tags, the company would see greater efficiencies and be able to pass on the savings to their customers. Maybe, maybe not. But three years later, Wal-Mart is nowhere near full-bore into the RFID realm with little to no cost savings, in any area.

Terry Coatta

Computers Still Cool (and Profitable too) http://www.acmqueue.com/modules.php?name=News&file=article&sid=362 The years following the tech bust of 2000 were not the happiest of times to be in the high tech industry.

Fixated on Statelessness http://www.acmqueue.com/modules.php?name=News&file=article&sid=361 Yes, it's true. I'm fixated by the effects that statelessness has on building web apps. It's probably not healthy state of mind, but maybe that's just the price one pays for being a developer.

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New article on ACM Queue: A Conversation with Steve Ross-Talbot http://acmqueue.com/rd.php?c.370 Merging the Worlds of Academics and Practitioners

From the Workflow Systems issue, vol. 4, no. 2 - March 2006

article excerpt: The IT world has long been plagued by a disconnect between theory and practice--academics theorizing in their ivory towers; programmers at "Initech" toiling away in their corporate cubicles. While this might be a somewhat naïve characterization, the fact remains that both academics and practitioners could do a better job of sharing their ideas and innovations with each other. As a result, cutting-edge research often fails to find practical application in the marketplace.

This is why the world needs more people like Steve Ross-Talbot. He has more than 20 years of experience leveraging cutting-edge research and applying it to real business problems. Recently he founded Pi4 Technologies where he and his team draw on the field of the pi-calculus to improve the ability to design, automate, and analyze business processes.

In addition to his entrepreneurial experience, Ross-Talbot holds positions on several standards bodies, including the Worldwide Web Consortium, where he is chair of the Web Services Coordination Group and co-chair of the Web Services Choreography Working Group.

Interviewing Ross-Talbot is Stephen Sparkes, CIO of Morgan Stanley's investment banking division. Sparkes is no stranger to the field of business process management, having spent more than 20 years working in technology for leading financial institutions in a range of development and infrastructure roles.

STEPHEN SPARKES In addition to your work with the W3C, you've been through several start-ups. Can you tell us a bit about the role of each company and the evolution of your research? STEVE ROSS-TALBOT In 1997, I started SpiritSoft. It was then called Push Technologies, but we rebadged it because the term push technology was getting a lot of bad press, as people were publishing content over the Internet and consuming vast amounts of bandwidth. SpiritSoft's mission was to build a generic event-condition-action, or CEP (complex event processing) facility. I had worked on a very large project called Hoodini (for highly object-oriented development) at Nomura International, where I was asked to deliver an active query facility. It turned out to be a special case of event-condition-action where the event is the change in the database, the condition is the predicate or query that you're wanting to subscribe to, and the action is to refresh your query results set, to remove things from it or add things to it, and then inform an application.

The only reason for doing that is to reduce bandwidth on the server so that you can start distributing the processing, and therefore you don't have to go back to the server to read your queries. You obviously change the programming model on most of the applications because they have to be event-driven. But if you're doing GUI interfaces, generally you have an event loop, so being event-driven is not so strange.

The key was to build something that was flexible around this notion of active queries. I left Nomura in `97 to start SpiritSoft in order to deliver a generic capability for event-condition-action computing because, at that time, I certainly felt that it was a very interesting and perhaps a fundamental way of building systems. These days we talk about event-driven architectures and service-oriented architectures as if they have been around forever, but there was a lot of stuff that went on before we got to this point, and event-condition-action and active systems were part of that.

I believed for a long time that event-condition-action was fundamental to the notion of autonomic computing and went on record as using event-condition-action to build workflows.

I left SpiritSoft in about 2001, because, like all start-ups, you have to focus on the things that you can deliver immediately, and SpiritSoft needed to focus on messaging, not on the high-level stuff that I very much wanted to do.

I got a dispensation to leave and do more work on event-condition-action, whereupon I met Duncan Johnston-Watt, who persuaded me to join a new company called Enigmatec.

At Enigmatec we went back to fundamentals. This really is the thread upon which the pi-calculus rests for me. When you do lots of event-condition-actions, if the action itself is to publish, you get a causal chain. So one event-condition-action rule ends up firing another, but you do not know that you have a causal chain--at least the system does not tell you.

It troubled me, for a considerable time, that this was somewhat uncontrollable, and certainly if I were a CIO and somebody said they were doing stuff and it's terribly flexible, I'd be seriously worried about the fragility of my infrastructure with people subscribing to events and then onward publishing on the fly.

So causality started to trouble me, and I was looking for ways of understanding the fundamentals of interaction, because these subscriptions to events and the onward publishing of an event really have to do with an interaction between different services or different components in a distributed framework.

Many years before I did any of this, I studied under Robin Milner, the inventor of the pi-calculus, at Edinburgh University. I came back to the pi-calculus at Enigmatec and started to reread all of my original lecture notes, and then the books, and finally started to communicate with Robin himself. It then became quite obvious that there was a way of understanding causality in a more fundamental way.

One of the interesting things in the pi-calculus is that if you have the notion of identity so that you can point to a specific interaction between any two participants, and then point to the identity of an onward interaction that may follow, you've now got a causal chain with the identity token that is needed to establish linkage. This answered the problem that I was wrestling with, which was all about causality and how to manage it.

At Enigmatec, we told the venture capitalists we were doing one thing, but what we actually were doing was building a distributed virtual pi-calculus fabric in which you create highly distributed systems and run them in the fabric. The long-term aim was to be able to ask questions about systems, and the sorts of questions that we wanted to know were derived from causality. For example: Is our system free from livelocks? Is our system free from deadlocks? Does it have any race conditions?

These are the sorts of things that consume about half of your development and test time. Certainly in my experience the worst debugging efforts that I've ever had to undergo had to do with timing and resource sharing, which showed up as livelocks, deadlocks, and race conditions. Generally, what Java programmers were doing at the time to get rid of them, when they were under pressure, was to change the synchronization block and make it wider, which reduced the opportunity for livelocks and deadlocks. It didn't fix the problem, really; what it did was alleviate the symptom. Read the rest of this article at acmqueue.com http://acmqueue.com/rd.php?c.370

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