IX.  The "Hype" - SOA - ESA - ESB

• A.  SOA - Service Oriented Architecture
  
  
  1. Ever since there were two computers, people have been trying to make them work together.  And you just knew that Sun's RPC, Microsoft's COM and DCOM, and CORBA would grow into something useable over the Internet.  I say "useable" because the best parts of those systems - cross-platform, high-level, interlanguage - were cloaked in complex ORB (Object Request Broker) systems, proprietary ownership, and confusing IDLs (Interface Definition Language).
     
     
  2. Enter the "web services dream"
     
     
     • XML loosens the shackles of proprietary hardware and proprietary languages
       
       
     • HTTP frees us from the complexity of ORBs, sockets, and all other connectivity issues.
       
       
  3. Now, apply these concepts to the enterprise as a whole, and the outcome is something like "service oriented architecture," or "enterprise service architecture," or "enterprise service bus."
     
     
• B.  What is SOA really?
  
       Again, we would like to recommend a couple of outstanding articles to you.*
  
  
  1. This article from Dr. Ali Arsanjani (Chief Architect, SOA and Web Services Center of Excellence, IBM) and Kerrie Holley (Distinguished Engineer, Chief Architect, eBusiness Integration Solutions, IBM Global Services) looks at SOA from within IBMs Service Integration Maturity Model ( SIMM) - "Maturity, Adoption, and Transformation to SOA (.pdf download)."  Check out the "Resources" link and comment on the article or discuss on the developerWorks blog!
     
     
  2. This article is from the O'Reilly xml.com WWW site.  It's by Dr. Hao He, a systems architect at Thomson Reuters and active member of the W3C Web Service Architecture Working Group.  The title of his article is "What is Service-Oriented Architecture?"  He gives down to earth examples in explaining the concept and has provided "related reading" links to aid you in digging deeper.  There's also an online discussion provided at that site!
  
       In addition, Syspro published a guide to SOA in 2006, which gives a good overview of SOA models, implementation, and applications.
  
  
  • Syspro on SOA:  A Guide to Service Oriented Architecture