This illustration shows that one OSDI subsystem can support multiple Oracle database instances and Oracle Net services. It shows the OSDI architecture in two tiers. The top tier is a box labeled "Subsystem OSG1." This tier is connected by a vertical line to the bottom tier, labeled "Services." The bottom tier is made up of separate components for each Oracle product or type of product.  The components are labeled "RDBMS ORA1," "RDBMS ORA2," "Net Net1," and "RDBMS TESTSRV."