\section{What is architecting?}

Architecting in product creation spans from {\it understanding} the {\bf why},
via {\it describing} the {\bf what} to {\it guiding} the {\bf how},
as shown in figure~\ref{fig:LWAwhatIsArchitecture}. Or in even more
popular terms: {\it do the right things} and {\it do the things right}

\FigureImposeWidth{LWAwhatIsArchitecture}{Architecting visualized}
{.6\textwidth}

Architecting is a job which is done by all members of the product creation
team, however the architect is responsible for the consistency and balance
of {\bf why}, {\bf what} and {\bf how}

A useful top level decomposition of an architecture is provided by the
so-called ''CAFCR'' model, as shown in figure~\ref{fig:MSintegratingCAFCR}.
The {\it customer objectives} view and the {\it application} view provide
the {\bf why} from the customer. The {\it functional} view describes the
{\bf what} of the product, which includes
(despite the name) also the {\it non functional} requirements.
The {\bf how} of the product is described in the {\it conceptual} and
{\it realization} view, where the conceptual view is changing less in time
than the fast changing realization (Moore's law!).

\FigureImposeWidth{MSintegratingCAFCR}{Five viewpoints for an architecture.
The task of the architect is to integrate all these viewpoints, in order
to get a {\it valuable}, {\it usable} and {\it feasible} product.}
{.8\textwidth}

The job of the architect is to integrate these views in a consistent and
balanced way. Architects do this job by {\it frequent viewpoint hopping},
looking at the problem from many different viewpoints, sampling the problem
and solution space in order to build up an understanding of the business.
Top down (objective driven, based on intention and context understanding) in
combination with bottom up (constraint aware, identifying opportunities,
know how based).

\FigureImposeWidth{LWAarchitectureHow}{Guiding {\bf how} by providing
five {\it how}-viewpoints}{.9\textwidth}

The {\bf how} of the product is created by many specialists. The {\bf how}
is guided by the architecture. At least 5 views are required for guidance:
\settoheight{\myListItemsep}{.}
\begin{myList}
\item functional decomposition
\item construction decomposition
\item allocation of functions to construction elements
\item infrastructure
\item integrating concepts
\end{myList}
Figure~\ref{fig:LWAarchitectureHow} visualizes these 5 {\bf how} views.

