At this point, it's pretty much taken for granted that everyone knows how SOA can be used to modernize legacy systems and integrate mainframes. In fact, it's so often assumed, it's been a long time -- over a year, at least -- since I saw anything that specifically addressed this application of SOA.

That's why I was pretty pleased to find this write-up on the topic by Tom Laszewski, the technical director of the Oracle Modernization Solutions team. I found it via AppInsight.net, which noted, “Tom’s done a lucid and convincing job laying out the challenges of integrating and leveraging legacy based assets.”

They're right. He has. What I particularly like is that the piece is very specific, identifying points where SOA can be used to integrate legacy solutions. He then outlines four specific use cases for legacy SOA integration:

1. Using SOA for Enterprise Information Integration, aka data integration, file sharing or file messaging.
2. Using SOA to Web-enable a legacy system, aka “screen scraping” or “re-interfacing.”
3. Using SOA to report off load using data migration, aka data migration, legacy operational data store, reporting modernization, or business intelligence consolidation.
4. Using SOA as an end-to-end, aka moving to a Software-as-a-Service model or legacy SOA integration.

In each instance, he looks at the problem the legacy system creates, the "context, (or, put another way, the reason you want to integrate the legacy system), the forces at play in the situation, a diagram (which generally references Oracle solutions) and an architectural summary.

Actually, it turns out the article is an updated version of a more Oracle-specific article written in October. If you're not an Oracle shop or not solely an Oracle shop, I'd opt for the Server Side version. It still references Oracle solutions in the diagrams and explanations of the diagrams, but it's considerably more generic than the first version.