The same task has produced what is arguably the greatest triumph as well as the greatest failure in software development. Air traffic control is a task where 24/7/365 (functional 24 hours a day, 7 days a week, 365 days a year) must be a law rather than a mantra. The national air traffic control computer system known as the 9020 was written using punched cards and is roughly 500,000 lines of code. Despite all the noise about problems and obsolescence, it has scaled up so well that it is used to control several times the number of flights that it did when it was developed in the seventies. The project to replace it, called the Advanced Automation System, cost several billion dollars and yielded nothing usable, although it did make the developers a great deal of money. Within these two extreme bookends there are several lessons to be learned and that is the point of this book. The author worked on the 9020 system and spends a great deal of time ruminating on how things were, from coding to the personalities of those who built it. Packed within this is one clear lesson. In all successful software projects, there is a small, core group of people who do the bulk of the true work. Enlarge that core, either by increasing the numbers or infiltrating it with bureaucracy, and the chances of failure plummet. This is the conclusion reached by the author in his analysis of why the Advanced Automation System failed. The secondary lesson is that the very stability of the air traffic control system makes it fragile and difficult to change. There is no easy way to make changes to the system, where the simple movement of a control knob several inches can create problems. There are lessons for developers sprinkled throughout the book, although it is sometimes necessary to read carefully to find them. Presented in the form of a non-sequential journal, the flow sometimes goes sideways, but it nearly always manages to make a valid point.
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Charles Ashbacher (CharlesAshbacher)
Charlie Ashbacher is a compulsive reader and writer about many subjects. His prime areas of expertise are in mathematics and computers where he has taught every course in the mathematics and computer … more
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Discusses the culture and infrastructure of software development, combining history, characters, dialogue, memoirs, and technical information. Describes software development's evolution from the early systems of the 1960s and 1970s to the present. Softcover. DLC: Computer software.