12.2. Service Fortresses
The term service fortress refers to a miscellaneous assortment of fortresses that provide shared functionality that is needed by multiple fortresses within the enterprise.
Many people confuse service fortresses with linked libraries. A linked library can be either shared (meaning that the same binary is shared by many processes) or unshared (each process has its own binary). A linked library may be written in an object-oriented programming language.
A service fortress differs from a linked library in that it also represents a significant amount of shared data. It is the data strongbox more than the shared functionality that defines the service fortress. The rule of thumb, then, is that if only functionality needs to be ...