Fundamentals of Software Architecture

Chapter 16. Orchestration-Driven Service-Oriented Architecture

Architecture styles, like art movements, must be understood in the context of the era in which they evolved, and this architecture exemplifies this rule more than any other. The combination of external forces that often influence architecture decisions, combined with a logical but ultimately disastrous organizational philosophy, doomed this architecture to irrelevance. However, it provides a great example of how a particular organizational idea can make logical sense yet hinder most important parts of the development process.

History and Philosophy

This style of service-oriented architecture appeared just as companies were becoming enterprises in the late 1990s: merging with smaller companies, growing at a break-neck pace, and requiring more sophisticated IT to accommodate this growth. However, computing resources were scarce, precious, and commercial. Distributed computing had just become possible and necessary, and many companies needed the variable scalability and other beneficial characteristics.

Many external drivers forced architects in this era toward distributed architectures with significant constraints. Before open source operating systems were thought reliable enough for serious work, operating systems were expensive and licensed per machine. Similarly, commercial database servers came with Byzantine licensing schemes, which caused application server vendors (which offered database connection pooling) to ...