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Large-Scale Complex IT Systems

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The reductionism behind today's software-engineering methods breaks down in the face of systems complexity.

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William Nichols

Glad to see someone exploring the issues from the technical side. There are multiple threads of technology-enabled (and dependent) operational processes that are being shaped by changes in the underlying toolsets. It's important that we as technologists are willing to acknowledge the "cross-disciplinary" issues, and the fact that current engineering disciplines don't permit deterministic application of the technical capabilities, but possibly more important now is the lack of awareness or understanding on the part of non-technical players, especially in the regulatory and business arenas. I'm currently working on regulatory and industry responses to the lack of standardized identifiers in financial services -- a contributing factor to why neither business actors or policy makers can get good enough information fast enough to even understand pieces of the "big picture". One of the things that stands out most clearly is the insistence of "those who matter" that they do not have to understand or consider technology issues, especially as to how they apply to implementing policies or procedures. Absolutely crazy, but taken as perceived wisdom that cannot be challenged. Quite likely to see some proposed solutions that ignore technology aspects and guarantee further problems (shortly) down the road. Very frustrating, and I encourage all to think about how exactly to convey the importance of understanding *how* something is done requires as much thought as *why* it is to be done -- at least if you care about *whether or not* it actually gets done.

CACM Administrator

The following letter was published in the Letters to the Editor in the October 2012 CACM (
--CACM Administrator

In "Large-Scale Complex IT Systems" (July 2012) Ian Sommerville et al. reached unwarranted conclusions, blaming project failures on modular programming: "Current software engineering is simply not good enough." Moreover, they did so largely because they missed something about large-scale systems. Their term, "coalition," implies alliance and joint action that does not exist among real-world competitors. They said large-scale systems "coalitions" have different owners with possibly divergent interests (such as in the 2010 Flash Crash mentioned in the article) and then expect the software "coalition" used by the owners to work cooperatively and well, which makes no sense to me. Even if the owners, along with their best minds and sophisticated software, did cooperate to some extent, they would in fact be attempting to deal with some of the most difficult problems on earth (such as earning zillions of dollars in competitive global markets). Expecting software to solve these problems in economics makes no sense when even the most expert humans lack solutions.

Alex Simonelis

CACM Administrator

The following letter was published in the Letters to the Editor in the October 2012 CACM (
--CACM Administrator

Reading Ian Sommerville et al. (July 2012), I could not help but wonder whether new initiatives and institutions are really needed to study and create ultra/large-scale complex artificial systems. We should instead ponder how the behavior and consequences of such systems might be beyond our control and so should not exist in the first place. I am not referring to grand-challenge projects in science and engineering like space exploration and genomics with clear goals and benefits but the ill-conceived, arbitrary, self-interest-driven monstrosities that risk unpredictable behavior and harmful consequences. Wishful thinking, hubris, irresponsible tinkering, greed, and the quest for power drive them, so they should be seen not as a grand challenge but as a grand warning.

Why invent new, ultimately wasteful/destructive "interesting" problems when we could instead focus on the chronic "boring" deadly ones? From war, polluting transportation, and preventable disease to lack of clean water and air. These are real, not contrived, with unglamorous solutions that are infinitely more beneficial for all.

Todd Plessel
Raleigh, NC

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