Architect Also Implements


ArchitectAlsoImplements.jpg
Architects of a housing development working on-site, 1942.

...an organization is being built to serve an identified market (OrganizationFollowsMarket) or markets. Going forward, the project needs the necessary architectural breadth to cover its markets and to ensure smooth evolution, but it can't be blindsided by pragmatic engineering and implementation concerns. Furthermore, the project needs to carry through a singular architectural vision from conception to implementation if it is to have conceptual integrity.

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A software project must broaden the scope of leadership without sacrificing depth and attention to pragmatics. Though developers are good at making individual design and implementation decisions, a project needs an overall guiding strategic technical direction. This usually comes from the architect. However, too many software architects limit their thinking and direction to abstractions, and abstraction is a disciplined form of ignorance. Too many projects fail on "details" of performance, subtleties of APIs, and interworking of components — or, at best, they discover such problems late.

If an omniscient plan were possible, one could solve this with totalitarian control. But even if that were possible, totalitarian control is viewed by most development teams as a draconian measure.

The right information must flow through the right roles; in particular, the developers must latch onto the strategic vision and carry responsibility for implementation. The architect, and to some degree the developers, must also understand the application needs and what they portend for the long-term structure of the system. But there should be a more centralized locus of strategic direction that keeps the project from floundering, makes sure the necessary details are attended to, and keeps track of the emerging "fit" of all the pieces into a whole. Sometimes this "fit" requires understanding low level details of component interaction, protocols, APIs, performance, or reliability concerns.

Therefore:

Beyond advising and communicating with Developers, Architects should also participate in implementation.

The Architect should be organizationally engaged with Developers and should himself or herself write code. The Architect may implement along with a developer using DevelopingInPairs.

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If the architect implements, the development organization perceives buy-in from the guiding architects, and that can directly avail itself of architectural expertise. The architects also learn by seeing, first-hand, the results of their decisions and designs: an important place for feedback in the development process.

The importance of making this pattern explicit arose recently in a project I work with. The architecture team was being assembled across wide geographic boundaries with narrow communication bandwidth between them. Though general architectural responsibilities were identified and the roles were staffed, one group had expectations that architects would also implement code; the other did not.

One manager suggests that, on some projects, architects should focus only on the implementation of a common infrastructure, and that the implementation of non-core code should be left solely to the Developer role. This may work in some projects; however, it is crucial that the architect have a strong feel for the application needs. It is by understanding recurring application needs that the architect can build long-term robust frameworks. If architects work only on infrastructure without an engaged appreciation of application needs, there will be a disconnect between the infrastructure (framework, middleware) and the application.

"It would be convenient if architecture could be defined as any building designed by an architect. But who is an architect? Although the Academie Royale d'Architecture in Paris was founded in 1671, formal architectural schooling did not appear until the nineteenth century. The famous Ecole des Beaux-Arts was founded in 1816; the first English-language school, in London, in 1847; and the first North American university program, at MIT, was established in 1868. Despite the existence of professional schools, for a long time the relationship between schooling and practice remained ambiguous. It is still possible to become an architect without a university degree, and in some countries, such as Switzerland, trained architects have no legal monopoly over construction. This is hardly surprising. For centuries, the difference between master masons, journeymen builders, joiners, dilettantes, gifted amateurs, and architects has been ill defined. The great Renaissance buildings, for example, were designed by a variety of non-architects. Brunelleschi was trained as a goldsmith; Michelango as a sculptor, Leonardo da Vinci as a painter, and Alberti as a lawyer; only Bramante, who was also a painter, had formally studied building. These men are termed architects because, among other things, they created architecture — a tautology that explains nothing." — [BibRef-Rybczynski1989, p. 9].

[BibRef-Vitruvius1960] notes: "...[A]rchitects who have aimed at acquiring manual skill without scholarship have never been able to reach a position of authority to correspond to their pains, while those who relied only upon theories and scholarship were obviously hunting the shadow, not the substance. But those who have a thorough knowledge of both, like men armed at all points, have the sooner attained their object and carried authority with them."

John Thomas [mail of 18 Mar 1997] writes: "C. E. Walston and C. P. Felix did an extensive multiple regression study of software productivity — reported in the IBM Systems Journal, vol.16, 1977, pp. 54-73 'A method of programming measurement and estimation.' [BibRef-WalstonFelix1977]

John continues, "As I recall, the proportion of architects who were also on the implementation team had a very large coefficient. It was a much more powerful variable, e.g., than use of a high level language or use of structured programming."

Though the architect should be able to understand the minutiae of development, it is not necessarily the architect's business to deal with detail day in and day out. Much of what the architect does is to be the keeper of the flame, the owner of the principles that the project follows: principles that in turn shape structure. Much of the structure can come out of a consensus process guided by the architect; in fact, in practice, that's much of what architects do. [BibRef-CoplienDevos2000]

A related pattern is GuruDoesAll from the collection of Don Olson [BibRef-Olson1998a, 153-154], which states [BibRef-Rising2000, 130]:


A newly formed team is given a project with a tight schedule, uncertain requirements, uneven distribution of skills, and new technologies. Let the most skilled and knowledgeable developer drive the design and implement the critical pieces. This can be an antipattern.

The important element of this pattern is to give the critical pieces to the most skilled and knowledgeable practitioners (DomainExpertiseInRoles and, of course, ArchitectAlsoImplements). But it also has elements of SoloVirtuoso, and can be thought of as an interim application of SoloVirtuoso in the context of a project that will mature out of the need for such a pattern.

This pattern should be tempered with ApprenticeShip, PhasingItIn, DayCare and others to move toward more of a peer team over time. (DayCare, in fact, talks explicitly about problem of people starting to say that "a few experts could get the project done faster"). Putting too much burden on one developer can lead to early burnout (see TheOpenClosedPrincipleOfTeams). It is sometimes difficult for a lead developer to give up the SoloVirtuoso behavior on a given project once having filled that role, so this pattern should be applied with care.