Agile Software Development
Автор: Alistair Cockburn /
CHAPTER 4. Methodologies XP Under Glass
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Часть 3
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Using the planning game in this way, the sponsors can http://www.storewom.ru properly play the two competing subgames: that of delivering software quickly and that of protecting the group's knowledge.
The above discussion is hypothetical. I have not seen it used. The reason may be, and this is the hazard to the scheme, that the people who are requesting new functionality have great allegiance to the current project and little or no allegiance to future, possible projects. In other words, they don't have a "duration of accountability" that permits them to adequately balance the priority of new functionality against documentation. Resolving this problem will probably remain difficult.
An XP team might consider less common and less expensive ways to document the system design, such as video documentation (as described in Chapter 3).
Restriction to Small Team
Many people exclaim: "XP doesn't scale! "
At this point, you should review, if you don't recall it, the graphs of problem size versus team size in the last section.
A well-structured, 10-programmer team using XP properly may be able to solve a larger problem than a 30-person team using a larger methodology. In fact, on the first official XP project, an 8-person XP team delivered in one year what the previous, 26-person team had failed to deliver in the previous year. So be aware of what the statement "XP doesn't scale" really means. XP scales quite well in problem size (up to its limit); at the same time, it does not scale in staff size.
XP, as written, has been demonstrated on projects with up to 12 programmers and four on-site customers. It may have trouble with larger teams due to its reliance on tacit knowledge. It is difficult to build extensive tacit knowledge without good osmotic communication, and that is hard to do with more people than conveniently fit in a room. A larger project team trying XP will have to adjust the teaming structures, interfaces, and use of documentation to accommodate the greater coordination needs of the larger group and the thinner communication lines.
I leave it as an exercise to the inventive practitioner to experiment with these modifications to XP.
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